What are all evidence of a dead PC /Motherboard /PSU?           
  or as some say I have a NO P.O.S.T PC's

No post means the the BIOS is so dead, that it can not start or never completes the POST (post code FF is fail and 00 is good, ready to boot media) Intels page on this topic is great.
A NO POWER symptom are no LED's glow, and no fans spin, HDD does not spin nor does DVD drive eject. A silent PC is Dead power or (or PSU bad or overloaded)

This Page is about hardware death, not software at all nor Windows dead or sick. (in fact I'm testing now with the HDD/SSD boot drive unplugged !) NO OS testing 101:
In cases like this the goal post moves to GETTING ONLY BIOS LOGO and HOT KEY SCREENS working first.
The 3 givens are:
  • Your monitor is not dead, (test it on PC #2 first?) If the power button acts dead on any monitor it is dead. (green LED ok, blinking may mean in sleep mode)
  • and you do have HOT USA 120volt  AC Power at  the wall outlet and arrives to your PC (no dead power strips or UPS in the this path) (and this not set to 0)
  • The monitor ports need to match your PC port and the correct one, many PCs 2 ports that look and are the same, but only one is active, (If a PCI card port is present only it works) (buy an adaptor if monitor has wrong ports)
Modern monitors have 1,2 or 3 input ports, make sure you manually set  the port to the correct port or set the port scanner (in the OSD) to scan all ports (AUTO) make sure the monitor is connected correctly to the PC.

If your PC has a Video card (PCI-e GPU card) try all ports on the card to a monitor matching port, do not use the other NON PCI slot video ports, called onboard Video(or iGPU) as they are off line now)
If that fails then:
Best is to test the PC with the iGPU VGA port only and the PCIe GPU card  removed. (at first)  {when testing use this order for testing, VGA if present at all, then DVI then HDMI and last DP} (BIOS will display ok on 1 or all)
  1. The PC is dead silent all fans dead for sure CPU fan dead and screen 100% dead, The PSU may be bad. (on laptop test the PC first with the BIG battery removed  (they can short out , then a new power LT powerpack)
  2. If still dead?, do the long power reset next.
  3. Did the 24pin or 4pin power plug from PSU to MOBO fall off? BOTH MOST be connected and power present when turned on.
  4. If the 24pin has purple wire if not +5vdc with PC on or off and AC power at the PSU power line cord the PSU IS TOAST ! (or very very rare shorts to that +5vStandby pin)
  5. Make sure the power button wires are not damaged and did not fall off  the connectors at each end of the wire set. (front panel power buttons do sometimes fall off)
  6. Next is the COIN cell,  life scan is 5-7 years, if PC parked on shelf for years, the battery can fail in 3 years time. (Intel spec latter)
  7. Is it still  dead?, see if the USB ports are dead. (I use  keyboard (caps lock key toggle LED) or mouse to see if it is dead, the mouse  upside down (wired mouse ) if it  glows good,  if not USB power is dead, so  PSU is bad.
  8. Test the motherboard, setup as a MINIMUM system,   see the full story here on that (or do the strip down tests)
  9. A PC   motherboard  will beep on most PCs for any gross errors, beeps mean that . One test is to remove all RAM (DDR) and hear the beep code for NO RAM.  If no beeps that means BIOS firmware is dead. (no POST)
  10. If still dead , bench test the PSU,
  11. If spare good PSU fails the motherboard is bad or something  or any thing connected to it can be bad (shorted) test all RAM 1 by 1, in DDR slot 0 ,channel A.
  12. The Motherboard can be tested with just 2 things connected,  the CPU and 1 stick of ram. (if the PC beeps or shows screen messages) Try other sticks of RAM for sure listed in the motherboard QVL RAM qual list.
  13. If still dead?, try a cheap low cost Celeron CPU in this PC, if still dead the VRM's on the mobo are bad, and that means the MOBO is bad. (CPU VRMs are low voltage voltage regulator modules on the PCB near the CPU)
  14. Tricks abound, power on with no Coin cell and no RAM. (pray) fully stripped PC, (just CPU,mobo, power cables and power on button) , repeat with no 4pin power plug to CPU then put it back and 1 ram back and test.
  15. Test with no coin cell present to force the PC to go to BIOS defaults (this can do the trick) , also old PCs have reset button , or set of pins next to power button, so shut this when power is on, for hard reset.
  16. If you just bought dead PC make sure some own did not kill the BIOS FIRMWARE with the wrong BIOS FLASH UPDATE.
  17. Last and best is  Port 80 , BIOS "POST card",  a card that fits the (PCI-PCI-or LPT25 (PRN) port) that shows post codes in hex. (but each BIOS uses different error codes) as seen here.

One fundamental clue above is that USB power is one of the first things to occure on all PCs' (in fact instantly) that is how for example on a DELL the F2 BIOS key works. (the keyboard wakes up and goes live)
If for example the POST scan can not get past memory identification scans, then  the KEYBOARD never goes live, nor will the mouse glow (bottom side glows)
I have a  USB tester (cost me $3) that allows me to see 5vdc happen on the port and does instantly.
(almost all PCs now allow the mouse to work even only running BIOS screens, if the mouse does not glow you have no power or dead CPU or the POST  hung UP !)
The POST or power on self test in ROM checks all critical hardware in the PC, for not only is it present and  not dead, but what options or types of devices are present, like CPU ,RAM and GPU   Video cards.
The BIOS POST must complete and not stall, if it does the PC is dead and BIOS is stalled, most modern PCs do not stall and will always tell you what happened wrong. (old PCs back in say 2005 were DUMBER then)

Case in point: (ugly makes the best examples) (video MP4 of POST stuck with bad ram, VGA port is dead due to this fact) The POST card told me what was failing.

I have one Intel old motherboard here that the USB power is good 5vdc and fan CPU spins, but the CPU never wakes up, nor does the mouse bottom glow with full 5vdc power to the mouse, and the screen is dead. (the mobo is bad)
The motherboard beeps 3 times if RAM bad and Siren sound for CPU overheated (smart that, if heat sink falls off !)
If all DDR RAM is removed, the MOBO should beep if not the CPU is dead. (or VRMs) (for sure if hit by lightening or other ESD power surge events)
The CPU can not run if it does not have proper DC power to it, from that 4pin MOBO plug.

Evidence examples are many and  plenty. (all are common and key to knowing what to do next) 
The  first thing to learn is that things fail and short, and PC dies, remove all things that can short.

  • The Fans must spin,  for sure CPU. (I do not cover fan-ess PC's nor high end silent PCs, just laptops and typical desktops and all have fans) {not notepads or the like}
  • Sounds from fan or HDD motor, heard.
  • Sounds of HDD spinning, it has motor and at 7500 rpm makes noise, if you get ear close to it or on it you hear that. (if not the PC has no power or the HDD is dead) if the HDD shorts the PSU shuts  down, too.
  • The CD drive (dvd) tray button must eject the try or you have lost power.( if the DVD drive shorts the PSU shuts down so disconnect it)
  • Screen dead is one evidence, but so is stuck on the below logo screen, and if logo is there see next line below.
  • Ok logo happens but BIOS is dead,  F2 or the BIOS hot key is 100% dead. (all BIOS hot keys are dead, is  FIRMWARE FAILING) No to PC makers use the same BIOS or HOT KEYs (RTM)
  • Beep sounds or better codes (P.O.S.T codes) codes means ERROR CODES or text the same.
  • Some Dells have a 4 LED bar, POST error device in the I/O panel (power on self test errors,)  (some are hidden on the front black I/O panel and can only be seen if glowing "DELL stealth"
  • The power button on many PCs can glow 3 colors or blink. The amber blinking on many a PC means I'm stuck in speed mode. (RTM , read your manual ,)
  • Or POST errors that blink the CAPS lock keys in CODE.
  • or Post errors that show on the SCREEN in white on black text. they all are clues, covered in your OEM service manual. (RTM) (get it and read it , no 2 PCs are the same for POST errors , sorry unless are)
  • Some PCs go dead and there are POST errors and others can fail and you get no signs of errors are all, just a dead screen and no error codes of any kind. (PSU dead tops the  list or  shorts in the PC)
  • A dead screen (called a monitor) will tell you "no signal, no sync, out of range or NOT CONNECTED like this)
  • If you have  DELL PC , the newer ones this decade have ePSA , onboard firmware BIOS diagnostics, that test all hardware for errors, but a NO POST PC dead can't get this FAR.
One thing to learn is that the PSU will not turn on or runs for 16/1000 th of second only, for any overload of any kind it discovers (measures) this prevents 2 things, fire/smoke and not blowing up $1000 GPU /CPU chip sets.
That number is 16mS or in users minds, the blink of an eye or less. ATX spec. is 1second or LESS.

By now the PC is alive , I hope.

Rumors: VGA is dead and gone by 2015 , well it is near 2020 and is not gone. (yes less and is expected this)
The entry level DELL Inspiron Desktop has VGA but the newer XPS is dropped (and is HDMI and DP only) Others at DELL are all DP. (means DISPLAY PORT)
If by change you have PC with only VGA and the monitor has no  VGA ports here is the cure.(or the reverse of that) The are adapters for all things on topic.

A minimum system  is:  ( PSU + MOBO + 1 CPU + 1 stick of RAM (QVL listed) + 1 power switch button.) NO USB, no PCI-e cards , no HDD/SSD/DVD drives connected.)

P.O.S.T LOGO's:  (no 2 PCs have the same look and feel here, they are all the OEMs ART, but BUT BIOS is there for sure (or as we say now UEFI) pure FIRMWARE resident on board (MOBO)
Once the BIOS LOGO works (below) try 1 keyboard USB , never any wireless keyboards !!!

BIOS is located in Firmware in the mobo, and needs no HDD or SSD drive conneced at all to do the POST. (and will even tell you , NO BOOT DEVICE found as the last step in the complex POST process)
This Dell BIOS is not dead, see that DELL logo that comes from the firmware and the bar on the bottom is the POST scan. (the HDD is even removed now)!!!  (HDD means hard disk drive, boot drive)
I have seen BIOS even stall in the middle of the POST scan and freeze (bad RAM or bad cards installed in PC) when POST ends the F2 and F12 key go live (means you can press those keys now)
If the F12 boot menu shows your drive missing, it may be dead, HDD do that about 5 years old.
The goal to reach and get is F2 working !!!
The below monitor is telling me  my PC is dead, the VGA port  and the  DVI is dead,
(all monitors have there own brain inside and tells you  when the VIDEO ports are dead) Make sure auto port scan is ON. ( it can also show, NO sync, or out of range errors.)
HP LE2000x, every monitor works similar.
Once the monitor knows all ports are dead, it then goes to sleep (by USA laws , low carbon foot print and all that bla bla bla)
The monitor goes to sleep if PC is dead, or PC told it to go to sleep, no kidding. (and good to know)

version 1.  10-9-2019