Is my PC dead? 


A dead PC  can have many symptoms (this page below is not about windows  dead, but is a true dead PC and is a  hardware failure.(just on this page)
A truly dead PC will not boot to CD/DVD/BR-D/HDD or a USB stick with say Linux demo ISO installed on that boot media..
We are checking all hardware first for the failure. (finding it step by step)
 Learn that the Power button has many possible states, and is controlled both in the BIOS and in Windows control panel power settings.
Symptoms: (based on all senses, sight , sounds, and felt, felt means at the least feeling fans blow air out its exit port, and even the power button might be dead)
I am not covering NANO class or  silent PC's.
This list has proper order. (the first goal is getting any life at all to the LCD screen, anything at all is good, not 100% dead is a good thing)
If your desktop LCD monitor is dead just test in on any other PC to learn in 1 minutes work if it is good or bad. (easy no?) If the monitor is dead try a new VGA cable (DVI./HDMI/DP ) or what you use.
PC's have a huge list of single point hard failures. (so dead PCs are common)
Do the LONG RESET first !
  • First is always (laptops) remove that silly old now shorted huge battery so the poor PCs VRM's are not overloadedremoved first it simply snaps off, or needs to be unplugged
  • Next is beep errors, or any form of P.O.S.T error codes, flashing CAP lock LED or even TEXT errors to the screen call live POST errors (power on self test)
  • The Fan must blow air, seen , felt or heard,  the fans must all blow and flow air, or look in  the BIOS and some show Fan RPM, and see if  the fan is DEAD.( is it all jammed up with lint?)
  • Next is POWER issues,  the  PSU is bad? or  the Desktop PSU is overloaded ?  or in this case the Laptop power pack dead or overloaded?.  
  • This ends my simple list of failures that are  so very common on most PCs made,  The at wits end tests are here. (see my strip down test here)
Check point #1, is if the PC is over 7 years  old the old RTC coin cell battery is now at end of life or dead, we simple replace it ,
We use device $20 DMM voltmeter to  test the COIN cell  for over +2.9vdc. ( some old Toshiba junk PCs have  soldered down rechargeable battery for RTC and other tiny note pads have no RTC coin cell at all.)
This battery is called the NVRAM CMOS RTC (real time clock) battery it also stores all BIOS configurations (raw data not machine code) In all cases if not found yet, RTM read the manual , and learn where it is first.
If fans blow good and no beeps  heard and the CD/DVD tray ejects (the button works on the try) then do step 6 next below for a dead LCD.
When I see beeps I am talking 2 things,  both are, BIOS P.O.S.T errors. Power on self test errors. be they beeps or Cap.'s lock LED blinking out codes. Do not ignore any POST error codes, they are first.
The 2 top fails on all laptops are 2 bad batteries, and then a bad HDD.
One classic post on a newer laptop was, "I have no large battery" answer sure you do , just because they made it cracker thin and moved it inside the PC does not mean it can't fail in 1 years time. (so common)

Going deeper into the story and testing.
What does dead  PC mean?:  (the screen never glows any pixels ever, is the true meaning of death,  others say it is dead if  Windows is dead and they are wrong.) 
Nor forget the DESKTOP PC can in fact have 2 VGA jacks and 3 more on the rear, called DP, HDMI, and DVI, and connecting the monitor to the wrong port, can fail. (If this PC has nice graphic card, use that only)
  1. A PC can get locked up in Sleep mode, or hibernate , Do the  Hard power reset now seen here, but  if the screen is only dim see why here, test the screen in dark room first. (up the screen brightness level control?)
  2. Full size PCs (99%) have a thing called RTC CMOS NVRAM coin cell battery  with spec. life of 7 years, if bad the BIOS can go totally nuts, even make BIOS dead ! Do not be tempted to flash the BIOS.
  3. P.O.S.T errors (power on self test errors (blink codes or beep codes are possible. These errors are not to be ignored,  as in FIX me FIRST!
  4. Fans are dead  are a sigh of FILTHY LINT packed up fans or lost power. If the CPU fan is dead the BIOS will not let the PC boot, (self preservation mode)  The Desktop has 2 fans or more and must not be dead.
  5. If Screen is 100% dead ? but  fans ok. ( no text , no logo graphics, "like HP, or DELL or ACER" no BIOS screens show up at all? at power on button, see my dead monitor or dead screen page.
  6. If the a desktop Monitor  attached works ok, then the PC is not dead, if the usage of  flash light pointed at the screen shows data now, then the PC is not dead, but CCFL back lamps are dead 
  7. Will not operate (run) on AC pack only (no laptop battery in place now) Try a new AC power pack, if this PC is Desktop try a new PSU (or test it easy with  jumper clip test)
  8. If  the  Fans screams fast , screen dead or not,  the PC can be overheating fast, (clean all air paths and vents, now.)   Or see this silly why to wreck a CPU, do not attempt this, please.
  9. If  Windows runs for a while, run HWinfo32.exe to see CPU temperatures. at 80-90C  the CPU and GPU chips must run cool and the CPU self shuts down at 90C , but on better PCs BIOS shuts down at 80c.
  10. If the fans blow, and BIOS screens look ok , the next tests are the  HDD tests seen here.( if these tests pass OKAY, then  the OS Windows it self is bad/corrupted.
  11. If windows is dead  ..,  (see windows cures here )  Or just fresh load Windows here.
  12. Last of all the PC may run for 1 second or shows hard power failure with a good PSU, we suspect power overload from shorted modules.   SEE how to Strip down the PC and find your shorts.
Once the BIOS screens show up Tokay  and  the fans work, we do more testing below:
In all cases a real top PRO shop will test the HDD first , as reloading the OS is not going to happen on a bad HDD, nor will Recovery work; nor windows repairs work with DEAD SECTORS. ( learn this and save vast wasted time)
HDD can be, good, bad or ugly , Ugly means weak ,Ugly means the HDD is EOL, end of life and has run out of auto repair spare sectors. ( it's like bucket of water with holes in the bottom for sure)
A new HDD bucket (analogy) that has a nice dynamic self sealing bottom that can self deplete after 10  years, then the bucket leaks water, and will get worse every day forward in time. (a bad or weak HDD is hopeless)
See not dead problems here)

PCs have this thing called HARDWARE HARD POWER RESET PROCEDURE. (ALL PCs made of any kind )   This resets 3 classes of faults. (ESD latch up, Sleep stuck or Hibernate mode stuck)
A laptop , we remove  huge battery that falls out bottom easy , we do that, and unplug the AC pack  to said PC and hold the power button  for 10 seconds, this PC is now hard reset.
A Notepad with it's stinky deeply hidden battery can be reset  the same way above if you are handy , but you can also just remove the power pack AC and push power button for 30 seconds and hope this works , and can.
Desktops , are more easy ,  it has no huge battery, so we unplug the AC line cord, and push power button (front) for 5 seconds, and you will hear fans spin for 1 second, this magic trick discharges all CAP.s  in the PC and is now RESET.
This trick can unlatch a PC, or end the sleep modes, forced. << most failures like this are caused by a defective sleep mode and is really only caused by running bad/missing or wrong drivers for key chips in your PC.
The PC boots and loads windows is a serial process if this process fails windows or Linux or what OS you run can not load and run and operate.
So on a dead PC a sharp tech knows this, and set a newer (less) goal. (and that hardware matters first of all, no OS runs on dead hardware ever)
If say sleep mode keeps failing stop using it turn that off, or learn to get good drivers for all chips in the PC with working sleep mode, your OEM PC maker has them say at my most favorite PC maker.

The goal is to get the BIOS screens  working, first.

If your shop has a spare PSU,(desktop) try that first or if a laptop a new AC power pack. (or bench tests the PSU)

One other problem is the OS randomly self shuts down .
The below shows lots of details on how to diagnose each class of failure and examples. (related to my page here is Black screens of death (more detailed) or windows blue screens of death here.
Next up are Examples: (lots and lots of example and a way to learn how PCs actually work to aid in accurate diagnosis)

First things First:
In most cases
,  a truly dead PC is in fact a hardware failure and never software.  (if that Linux demo disk boots and runs ok, you now know the PC is ok, but the HDD can still be bad and we test that next the HDD fully !)
If your PC  was made in the year 2008, and has Nvidia , graphics chip (GPU) the chip was bad then, the solder ball horror (BGA chip) (sorry !)
If the screen is not dead and BIOS screens all work I can in fact boot to 6 or more things on my PC (HDD0, HDD1, DVD,USB port 1,2,3,4 SD Cards, and more) So as I stated before this is not dead PC at all.
The top cause of problems on all PCs are both batteries are now dead, or worse shorted, replace those old batteries they do not last 10 years,  7years on coin, as low as 1 year on the BIG battery.
The RTC coin cell needs to be replaced at 7 years max age.  (super thin Notepads do not have this coin cell, it uses the super thin large battery to do  both jobs) 
The big battery  may only last only 1 year,  the battery maker has a web site and you can  read the pages on how abuse can shorten the life of your battery greatly. ( endlessly deep discharging it will)
The PC runs forever with the main big battery removed,  running only with the AC power  pack plugged in (both pack cables connected)
Some old Toshiba's have to be turned on to charge (for 12 hours?) the very rare, RTC NiMh battery that only these PCs used. (by now most are dead and leaking nasty fluids)
Some old PC 1990's  even more strange batteries, seen in link below:
The RTC COIN CELL battery is easy to test. (with any voltmeter made) some relic PCs  have very odd cells or  a hidden RTC cell  ,marked  DALLAS (now Maxim)
Some tiny notepads (cell phone like) have no RTC battery (coin) at all, they use the main inside large battery  only, these class of PC have only 1 battery total, unlike real Laptops.
The top 3 failures on PCs are,  BIG battery bad and worse shorted, then the RTC coin cell bad, and HDD dead, or wounded)
The BIOS screens can be totally dead if the RTC is dead, or can not boot (Some BIOS's "cheap" have very poor POST warnings or none)
( This is because early POST tests see the corrupted NVRAM (RTC battery dead) and just halts or shows CRC errors then halts to protect the system )  < Each BIOS made has a personality (vast versions made)
The RTC battery must good. (test it or replace it) Some tiny thin PC note pads tablets have no RTC coin cell,  because the Tablet has only 1 hidden thin battery inside that does all battery functions as one.
Some PC tablets have no fans, but most laptops do, and for sure desktops have 2 fans, or more. (and silent NANO PCs have no fans)

Inspections and other odd tests you can do, including wiggle tests, power on PC is just 2 wires, and if loose bad, or damaged, can cause PC to die or to allow it to turn on if you wiggle wires, and Re-Seat all power connections.
The 3 top failures all PCs are batteries bad or worse far worse if shorted, remove it and run on AC pack only (laptops)
The next is CCLF failures, PCs older than 2010 this is #1 cause of dead LCD back lamps.
Next is bad AC power pack or frayed cables to same  then the PCs Laptop power jack cracks on the outside or the inside.
Main battery removed, OK?  it must be removed, they love to short out and overload power rails inside the PC.
Next is :WIGGLE testing (laptops ) sure re-seat all cable first.
If wiggling the power pack DC jack as it enters the laptop makes the PC run  (or die) , then you get to replace this (or this pig tail jack)
As you just learned POWER is first no PC runs lacking power, (same with your flashlight or other battery operated toys) Power means here correct spec. voltages under load.
What does spec. mean?, it means factory  specifications: (electronics chips have rules and if not obeyed, they stop working until corrected) See PSU spec here.,
The power pack must be rated for your PC, Volts, Amps, watts and plug type and polarity. (laptops)
Yes that is 5 factors must be correct, more watts is OK and same for Amperes ratings.
Some PCs need a 90 watt pack ,minimum or even more. (only your OEM maker of your Laptop has this answer) On average 65watts is common, but is  not a rule ever.

The wiggle test can be as simple is moving the AC Packs, DC plug as it enters the below JACK by putting pressure from the sides, 90degree's apart each of 4 times, and if power turns on now BINGO.
The word power means the voltage is at spec, and not full of noise. or your PC has the CAP.'S  Plague (so common in 1999- 2007)
Or you PC has the 2008 Nvidia Solder ball GPU GBA failures. (first no lead  (Pb.) did this. (and dooms the laptop this)
Jacks DC power: 
The inside of the jack can crack and fail, and the solder tabs too, can crack in may ways, and are seen on cheap laptops only. This left photo is just moments from being soldered back down,.(super hard to do this)
I call this the HARD jack and fail at the drop of a hat they do, so don't buy PCs that use this for power.

If lucky below, you have this easy to change out JACK called the Pig tail jack. This jack is seen on better quality laptops below.

As you can clearly seem things can actually break. The best laptops use this pig tail above so it will not fail. but the pigtail can fail, and is easy to replace, unlike the HARD jack above.

Fans: (can all be seen to spin, heard or felt to blow air)  (some tiny tablets have no fans at all they use heat spreaders inside is why.)
First off the main CPU fan is operated by BIOS firmware, (and windows if it wants to )
The BIOS can in fact stall dead any PC that has a fan that is dead at 0 RPM, as that will cause overheating so why boot any PC  with a dead fan, many a PC are now dead like this.
The PC is turned on and DC power flows, the CPU boots the BIOS firmware instruction codes, and the BIOS wakes up and  runs the fans fast (it runs it fast and if CPU is not too  hot it slows down)
The PSU runs its own fan, as does the GPU.
The BIOS now POSTs, it runs power on self test tests.
 It my present beep codes (or flash  specific LED codes) to tell you what is wrong (read the service manual on your exact PC) ( we always diagnose this first)

If the fans all spin and blow air and PC does not overheat, then it is not a totally dead PC.
All PCs self shut off if the BIOS sees 80C or the CPU itself (Intel Inside magic) it too will shut down a PC at 90C (194F "Fahrenheit" gringo imperial measurements)
Most desktops have 2 fans and all 2 must spin, or it will overheat. (Laptops mostly have 1 fan and it must do its job or it will fail)
My PC has 3rd fan with optional super fast 3D GPU card (or this video card overheats too)
The basic 2 fans  must spin and blow air (heard, seen and felt) yes we use 3 senses to prove this out. (as in seen not to stall fan or packed in lint) Click overheat above, to see why.

Next is beeps and blink code errors, CAPS lock key blink/flash codes, write them down first,  (flash flash flash, pause ,repeats) then look it up in your service manual. (relic PCs beeped but not now the flash LED codes)
Better PCs also send text to the screen called P.O.S.T error codes,( Power on self test
Some PC blink the CAPS lock key with POST error codes, (bad ram, bad VGA chip, etc)
Some desktops by HP and DELL have 4 LED POST error LED panel on the rear showing POST codes too.
Some Dell desktops (Optiplex) have rear LED group 4 LED that use a 4 bit binary error code cover fully in the dell manual. ( for sure has that) Dell and HP have the best documentation in this business, IMO.)
Read your service manual  for true and  accurate POST error code meanings, learn now that there are no BIOS standards on codes, (blinked or beeped)  silly yes, but always a pain in the ash can.
The screen dead ?, but PC seems to have power is here. (fans work).

This section is for exact EXAMPLES:
BIOS Screens are next: (make real sure Data and time are set correctly and holds, after a full power cord cycle of the PC) (laptop huge battery is not installed on this WHOLE PAGE I MADE)

If you PC is 7 years old or older the RTC tiny coin cell battery can be dead.(or weak) and BIOS WILL GO nuts  as will time of day and date , as seen on the BIOS screens. (5 to 7 year life is battery makers spec.)
The maker of the PC will pop up  a graphic ICON like this below, if you see this or text of any kind the PC is not really dead, at all, only the OS (Windows is dead or HDD dead)
As you can see this PC is not dead, because fans work and BIOS screens all work perfectly (each maker of PC uses different screens and different hot key to get to all screens of BIOS)
AS YOU CAN SEE THIS PC IS NOT DEAD, windows  can be  dead, but not the PCs BIOS screens. (screens good, fans good, time if day correct in BIOS, and you see this below the HDD tests are next.
This  screen (boot) is a BIOS FIRMWARE  message, The "ESC key" works on HP only, other PC prompt with different hot key. (F1  or F2? and more)
The HP you power on , hammer key ESC, then hit F1 key for the HP information page.
BIOS works and date is correct, what next?
The next thing to do if you see the BIOS screens work is to do a Operating system (OS) full recovery or startup repair, as covered fully at (or do as you OEM PC maker tells you in there service manual)
In the BIOS pages, check date and time first (system) if wrong date the RTC coin cell battery is dead.(or near dead)
If the BIOS shows your HDD 0 , in the boot odder the HDD maybe good, if missing there, the HDD is dead, and for sure dead if the HDD does not spin heard with your ear. (SSD are all normally silent)

If the PC is not dead and BIOS works then reload the OS.
On my PC the HP F11 key, is the magic recovery key for Windows full day 1 recovery, this key F11 is different on other PCs.  This topic is covered in your PCs service or users manual, read the chapter on RECOVERY.
If you are locked out of the BIOS with BIOS Passwords set, the cure is here.(or far worse BitLocker(tm))

The below covers what to do if the BIOS screens are dead.
No text and no logo?,  See causes of  dead monitors or screens here.(covers dead monitors or dead CCFL lamp tubes)
If the PC is silent that is a true dead PC, and will not have screen messages of any kind. (if fans are dead the PC may turn on and promptly overheat and shut off , by design!)
In most cases, no fans, no screens, death,  but not all the PSU is defective.
All PC's have a PSU, the Laptop has 2, (1 battery and 1 AC pack ) and with  on-motherboard VREGS aka: VRM) VRM means voltage regulator modules.
If the PSU tests ok, by itself then the motherboard, is bad (unlikely) and for sure the motherboard has what I call power overloads. (or the last person inside forgot to put back the AUX power plugs )
Overloads are shorts,  there are 4 classic  Von Neumann ways to short , (DC power rails, data bus, Address bus and control bus) The Harvard architectures , is more closer but what Intel chips you run , wins all bets.
The issue is shared resources, as seen on a bus. ( modern PC have many  and shorts on any of them end in PC dead) We then do the strip down tests.
PCs have vast types of single point failures, so when any PC fails, keep your mind open and do not ignore all evidence seen or heard.

The PC IS NOT DEAD  and  the BIOS SCREENS  work  ok  and date and time holds accurately INSIDE BIOS !:  NOT DEAD ! When we say dead that means hardware is failing , not Windows.
If your  PC was truly dead you could not get to the below.
Windows can be dead and the PC is 100% in prefect condition
  (A PC  can have 4+ devices, media at the same time (boot order page) that can boot) so if any can boot then the  PC is not dead. (HDD dead sure, or even simple OS corruption)
The HDD can be bad,  or the OS totally corrupted.(infected) but we always test the HDD first fully. (No OS made can run on a bad HDD of any kind, for sure if S.M.A.R.T tests fail)
Here is a list of order of testing the HDD, from easy to harder (I just boot my demo disk Lubuntu v17 and run the SMART tests) << all techs, have this in their KIT.
  • Remove any CD/DVD disk first, then remove all USB memory sticks or USB external HDD now (or external CD/DVD drives ) now. (we want only HDD-0 to boot)
  • In the BIOS pages the HDD-0 is messing sure it's dead totally if missing here. It shows up in boot order page for sure, if not it is a dead HDD or on a Desktop the cables to it fell off, 1 or both.
  • Next is BIOS HDD testing if present.  HDD drive test page
  • All HDD issues/tests. HDD and memory tests, be smart to do that now.
  • I put my ear to the  side casing of HDD (never do this on SSD, or M.2 drives) and if the motor is silent. (silence is  a dead HDD)
   If the HDD tests ok, reload Windows.
   or RTM read you manual on YOUR PC model (at your and read the chapter on RECOVERY , it is there just read your choices and do them. (my HP PC is the magical F11 key) 
  Examples below:  if this fails the HDD is bad or dead.  FOR SURE.
Sadly some PCs do not have this BIOS page test, at all, (cheap PCs) My HP do. The test is harmless, it does not damage data or the OS.
The above test is crude and if it passes we always run the full S.M.A.R.T tests next. As see here.

HDD BOOT ORDER:  (each BIOS looks different here)
Some just show HDD0 , others will even (nice) show the PnP ID message truncated (shortened)
Note the below shows the 
Matsushita drive. (a.k.a, Panasonic)
(if the boot drive name is missing here, that means the HDD is dead) This words next to UEFI: "are plug and play identifiers" if missing the drive does not talk !
Best is to look at your HDD, read its label and know what you have first.
Be that it :(Seagate, WD, Toshiba, HGST or my M.2 by Samsung and lots more makers of HDD (or lots more SSD)
Watch out for some drives newer are FIP/SED rated and have a lockout password that can not be reset. (read the datasheet only your HDD first)  (learn if a FIPs drive can be Re-Purposed) (or here)

A 2010  HP laptop Elitebook Below.
With my Linux boot USB present. (my Laptop has 2, SSD drives now, one is in place of DVD drive using a caddy seen as upgrade bay here)
Learn now that there are endless 1000s of BIOS made, some are brick stupid and no changes allowed, (notebook toys) or some like the below are almost endlessly granular. (the best are!)
So if you turn off the CD below, it will never boot CD disks.
Never ever turn on PXE, as that only works with an enterprise grade, boot server, that you do not have.  I now have a 2nd HDD in bay 2 but is not bootable.
UEFI on my PC is 1/2 baked, that means it will never ever be fully revised and working.

Keep in mind no 2 BIOSs are the same, and varies by year, by generation and by OEM contract rules.
Old legacy PCs . 
This is 2007 a relic BIOS and the HDD(harddisk) does not show the ID messages,(PnP) just the word HARD DISK means it does ID itself (the HDD is missing here, it is a  dead drive.)

Now last and best of all for any person working on PC's (I boot to my  self made Windows live PE w7 disk) So I can run HWinfo32.
Run HWinfo32.exe (portable) free, of charge to use.   (and for sure malware free,, clean) 
The below is my z270prime PS with 2 HDD and 2 SSD M.2 cards.
As you can see you don't need to remove the HDD to read the label on top to see what you own and which one boots.
I can see them all here, and  my 256GB m.2 is my boot drive, and therefore must show up in BIOS as my boot drive.
I booted to my USB Windows 7, looking for missing or dead drives. None are dead.

Keep in mind toy grade PCs, will have no BIOS screens at all to access. They are also (may) only boot from HDD0 and nothing else is offered or allowed.
(it is frozen to HDD0 boot for ever, so if the HDD fails the BIOS just opens up this dumb BIOS screen and freezes after all it is too dumb to do any thing else, but some do beep codes for dead HDD )
Watch out for your kids playing with your PC,  they might play in BIOS and set the HDD0 to no boot.
YBMY, your BIOS may vary , actually they ALL DO.
One other bad fact is that most PC makers do not document there BIOS or revise the BIOS 15 firmware freaking times, then not update the BIOS Manual or flat refuse to document it at all.
No man on earth knows all BIOS made.  (due to  this fact above) I have seen 1000's, but mostly forget older than  10 years ago. (geriatric me...)

STRIP DOWNS, or Naked Motherboard (mobo) testing can be done like this. (a.k.a. Fault isolation.)

Below is The ASUS mobo and do not ever hot switch (swap) any of these plugs, unplug the PSU and push the power on button for 5 seconds, to discharges all Capacitors on the mobo, or BOOM happens (thin wallet).
The ATX12v spec states you need V2.2 ATX PSU to get AUX jacks do so or the PC will be DEAD ! (or crashes endlessly, and will drive any human slowly mad)
the jacks here I call AUX, and most top MOBO use at least the 4 pin and GPU the 6 pin.
The Asus pages now how to run non gaming PCs it only 1 VRM plug.  (I say don't ) buy and use the correct PSU, OK?
end desktop talk:

Laptop strip downs:

My HP 8540w PC, below: (have many in the family love them I do, robust ! and not frail )

I cover all Isolation (pull) tests again here, in the PSU page.

The laptop mobo may look like this.  I have the fan spinning fast, the stock screen attached, at top red arrow., USB keyboard works, the screen BIOS Information page works.
If PC beeps for blinks fatal POST codes, we up all modules seen below, 1 by 1 , until it wakes up. 
(I pulled the HDD, the DVD drive, the  SD reader, the secure card reader,the Modem , the wifi card and the USB outrigger card) I tested the RAM 1 by 1. When the mobo wakes up  its BINGO city, no?
I can also remove the screen below and Jack in my nice VGA monitor to test if I have BIOS screens, the jack is D shell shaped, and has 15 pins called VGA port. We always do this first before the TAKE DOWN !

See my PC above, it has video card, that allows better testing or upgrading the video performance with 4 cards offered by HP,  (love my HP 8540s) and my favorite DELL keyboard, I buy them in bundles used.

The power button:   (is very programmable, or configurable in many modes ) on,off, sleep, hibernate, or RTC timer activated.   (do the hard reset first)
If you are confused, in Windows, what to do , then go in to control panel and click power icon there, and set the power mode to prevention mode. no sleep of any kind no screen time outs. (like you do using a projector)
If still not happy, here are the BIOS setting that can be set wrong.   (I have one PC that can turn itself on or off based on time of day, in the BIOS) Best is look here first see what you have.
The power states ACPI  for G1 to G3 and S0 to S4 are here.
If the power button fails, force the PC into G3 mode, mechanical off, do the hard reset.
Hold the Power button for 10seconds long and G3 full power off is forced.
If BIOS screens are dead, your PC has  serious power overload (shorts) or a bad PSU.

One more naked PC: for fun and smoke is never a good sign for sure running the PC on 240vac with the PSU set to 120vac, oops you let the smoke out. "vac" means voltage alternating current.

Grim examples and humor.

version 4:  10-10-2018  (covering the most common old PC failures and all Desktops,  but not covering tiny notpads or NANO silent PC's)