B.I.O.S ISSUES ALL.           

Basic, Input output system. (BIOS)  - a.k.a. UEFI now. 2008+ (Windows 8 + started to use it.)    If you think this topic is complex,  google BiosCenteral , ouch.
I run a nice ASUS Z270 motherboard and it has CSM (aka; DUAL BIOS ( means BIOS + UEFI mix  or not)
HP start date for UEFI   mid-October, 2012 at HP.(later than other makers of PC, late is good? and great if bug free!)  Most PC floating about  run very buggy UEFI and many not know it.
How does BIOS flow (order)?

Bios is ROM, a "read only memory", hard coded with intel (or AMD) machine code instructions, also called FIRMWARE.   Why is BIOS hard to understand?
When you you power on any PC this is the first thing that runs (executes) this ROM.
This is why checking BIOS First, with all BOOT issues, is so important, it's first. (as they say "first things, first:)
For BIOS to run at all or error free , you need 3 things, Good power, A functioning CPU, and 1 stick of RAM. (to see it run?, takes a good GPU chip, Video and sure the screen connected)
On more thing an  index finger to hammer the ESC key (F10 older) (other PCs work the same, but the magic key is different)
A short list of reasons for dead BIOS is here.

B.I.O.S:  (no matter if called, "Setup" by HP or UEFI today)  lets avoid the name game and just use  good old "BIOS".
Bios was introduced in 1981 with the first PC,  that booted to Floppy only, then later, HDD. (PC1,2 and  XT) 36 years, of BIOS.  (the first BIOS had no hot keys, you ran a bios-setup.exe off a floppy)

In all cases , BIOS must work  at power on button demand by you or you PC is dead or has lost all power.
The screen must shows this, (or the like kind)
Unless  you turned on BIOS PASSWORD (PW) feature. The screens all work,  do not forget that some PC I can PW lock only some BIOS screens.
(at power on, and hammer the F10 key(old) or ESC key (it prompts you every day with what key to press?)

What is power?,  well that means the PSU is not dead , the Laptop main battery is not shorted , the power pack to laptop not dead/weak, or the COIN CELL BAD.

First off the screen must not be dead. (bad monitor, dead CCFL , if the screen not once  shows a line of text then the screen is dead, or power is lost) (on a LT remove the main battery first)
BASIC input output System:
Aka, as BIOS or the newer name UEFI (and vastly more secure and complex)
BIOS is located in ROM and is FIRMWARE or Software in Silicon,  the chip is EEPROM memory called FLASH®  Flash EEPROM does not need uV light to erase it, like back on the first EPROM days of HP PC 1984 (first laptop)
Its called flash because its electrically erases and then can be burned fast. (a double flash feature , if you will)
This chip with code inside, X86 code, always runs first.  (in Real mode) I do not cover UEFI.
This ROM code runs first and is what    BOOT STRAPPING  means, the ROM runs Power on self tests then boots to the HDD#0 (default)  BIOS boots what ever in on your HDD/SDD. If Windows is there it boots windows, or linux or freedos. what ever.
The BIOS has a  boot order page,  that decides, what media, is to boot up first,  it and only IT decides this and is your choice.(means go there and look)
The PC can also roll the boot, if one media  fails it tries the next.  (BIOS logic does this since 1979) (the first systems needed a setup.exe program to reach BIOS, PC x86s back in the glory DOS days)
To get to the BIOS screen is easy, power on and hammer the ESC key (HP only , and last 10 years for sure)

See my list of reasons, that  BIOS is dead, here.

See my  INFORMATION , screen below (obviously the screen is NOT DEAD nor black)
 This is the first page a technician pulls up,  to see if some PAGES are missing, there is a memory check here and HDD test. Do that?
Do the HDD test there?
Photo 1: BIOS INFO SCREEN F1,,(a circa 2009 PC) HP Elitebook 8540w.  The screens below all work, even with the HDD removed.
 I pressed ESC at power on, then pressed F1 on Newer PCs, the older PC you hit F10 key hammered at power on key, and then do what the screen tells you, (a menu)
I will go in to details here as HP seems super afraid to document there BIOS fully, unlike say buying new mother board from ASUS and wow, great documentation there (yes, I like good documentation)

If you get this far ,. BIOS IS not dead, neither is the PC dead, nor is the PC BIOS password locked. Power seems to be okay.
The next goal once you have these screens is are the BOOT DEVICES and there order, (enable them and set the boot device order as you please)
All devices you need to boot must be enabled first, (some PC do not do that by default (reset))  My Disktop server, boots to PXE thin net server. by default and fails to boot, until YOU CHANGE IT.
This is in the BIOS TAB screens  seen below:
This section is to cover boot order only not DEAD BIOS.,

The more complex page on black screens of death more well   fully covered here.
Some really wise things to do , is,  run the PC with no Big huge battery installed, run the memory test in BIOS, and run the HDD test in BIOS if it has  this feature in BIOS. (look for them)

This is my HP BIOS ESC page,  page 1 in BIOS is here, F9 is boot on the fly page. F1 gives you  the screen page seen above. We first go to F10 setup.
F10: note the 3 tabs.  System configuration and device configs, is next, go to device Config and turn on all devices you want to use.(or boot to)

I will now show a few more screen so you can see HOW HP does this.
The HDD can been unplugged and these pages all work. (all but F11 recovery features F11 needs folder on the HDD to recover...) as can the DVD drive pulled (removed, or if a desktop cables pulled to it)
Here is a very old BIOS, boot screens, full setup mode.

All  (IBM spec) PCs have this, some less choices, but all have these basic screens (menu's BIOS).  Most consumer class PCs the HP manuals lacking , for coverage on BIOS, and on the cheapest HP new models the service manuals are not even available , even with hard cash offered (HP was the best ; where are they going now?)
As you can see my BIOS is partly UEFI certified, and is complex secure boot and rules, that I turned off.  2012 year is the magic year for HP fixing UEFI fully. (It will never be fixed on mine and for that I am grateful)
Most PC makers started support for UEFI at Windows 8 release.  (but all of them are full of BIOS bugs, nasty and some very bad, even making the PC useless to anyone)
Not only that horror but the UEFI rules dictate no regression path, (omg that sucks, so if the newer verion has worse bugs than the last, you can not go backwards, what a load of crap that is !)
My PC can boot to, 2 SSD, all USB2 ports (many USB memory sticks ) SD CARD and more, it is obvious below. no?
IF the CD-ROM (mines a DVD) is disabled, it can never boot ever, so turn it on if needed. This is Circa 2009 PC:
If the HDD will not boot look here first.  and run the HDD test on page 1.
As you can see I have MBR boot enabled and aka, called LEGACY by HP. ( I like MBR best) and UEFI off.
If my HDD goes South, (fails) I boot to a UDIsk, Udisk is USB memory stick with LINUX or Windows PE, LIVE (w7/w8 & w10 I have ready 24/7-365) to do that I push F9 at boot (power on) and change to that on the fly or it go to the screen above and move USB hard drive  to top line.
Watch out for full UEFI PCs turn off safeboot or you can not boot from DVD or USB STICKs (means udisk or usb thumb drives etc)
The mind set with the UEFI geeks is all media you have are infected with virus...... so is disabled now by default 2012 and newer PCs.
My HP calls the USB STICKS like this.
Note carefully here, I can put Linux on my 2nd drive and boot there any time I want.  (upgrade bay on mine has a DVD removed and caddy there, with 2nd SDD drive there, running any OS I WANT)  
CD-ROM means DVD in my case, can be bluray too, BD drive. (optical drive is better name, sure)

Hints on topic:-
This PC has  SD card slot (Camera flash card) and can boot lightning fast off a video grade SD card.  (or load and OS using this very very fast port slot !!  And advanced trick !)
One could remove the HDD and boot to the SD forever, running say LINUX live boot.  (yes,  there are lots of fancy and fun things you can do ) and never get a VIRUS again, due to each boot runs the LIVE OS as DAY  1 clean.
One can also run a Virtual OS and gain the same protections at every boot. Virtual-box? (I run Ubuntu 17 that has only 1 exploit listed, and run it under w10 -Hyper-v option, I use this for banking only 2 clicks and bam Ubuntu runs.. from W10, love it.)

The final ACT:
Now you have the HDD 0 device enabled and it is now in the top of the boot order list,  the BIOS JUMPS TO, and runs the OS will now boot up that, if it is still there and not corrupted. 

Windows or other OS installations? (fresh)
Installs? are easy if ?:
If you can not Install Windows? from any boot device, do this, first. (2012 and newer PCs)
  •  BIOS SECURE BOOT is turned on. (so turn it off, and make the device you want , first in boot priority or use the F9 key to do boot on the fly)
  •  Secure boot blocks booting from non normal master, HDD/SSD.
  • The legacy boot order set correctly and BIOS  USB boot devices turned on for USB and for CD/DVD.
<< Legacy on, and secure boot off.  Now you can boot a DVD or USB memory  STICK.

Why is BIOS so hard to understand?  "BASIC Input Output SYSTEM" known long long ago as ROM MONITORS." is now mutated to nasty UEFI firmware. (in time it will get better as HP updates it 10 times, ouch )
 {now called UEFI, it's FIRMWARE, software in SILICON it is , most times it is stored inside advanced super FLASH EEPROM memory like those from MicroChip(tm).} 
The BIOS runs POST tests, power on self tests and then bleeps or blinks (legacy) out codes , with vague hints that confuse many, yes, BIOS is stupid,  and will tell you BIOS is corrupted when only the RTC coin cell battery is dead.
BIOS  is only the minimum intelligence (contains machine Op codes) in the system it runs with the HDD and DVD drive removed.(f11 key dead sure missing any HDD)

ALL PCs run firmware driven POST tests, testing most  harware for errors and is CRUDE, and  and will fail easy even with a dead 5 year old RTC coin cell battery.
BIOS's  last job (in sequence) is to pick and run  a boot device.  or boot to it. (and order of boots)
First learn that the BIOS ROM does not forget,  It in fact lasts for more that 100 years.  (I have top instruments by HP that is 34years old with huge banks of EPROM memory, and not one bit or byte lost, in  any bank.)
This fact above does include kids playing inside any PC or ESD zapping the Flash ROM there on the MOBO, careless of the facts of Electrostatic discharges, humans to electronics.
Or some kids playing, lets flash the EEPROM to death for fun or  playing that silly inane game. Nor if the PC was hit by Lightning , omg bad news that.
Read how BIOS CMOS gates do not lose charge, even after many decades (by DESIGN) and endless topic and all true.  (the gate insulation is perfect!!!, is why, with QA processes to back up that claim, a fact.) 
What does fail and often is the silly RTC coin cell battery,  99.9% of all Checksum failures here are the battery and the CHECKSUM errors that result every time, and and the loss of time and date in the BIOS pages.
RTC means Real time clock chip, that is correct, your PC has   wrist watch chip deep inside your PC that keeps time of day and date .(it's not optional, it must keep time)
On some newer HP PCs the screen can even go dead. (only Caps lock LED blinks codes work now (post codes they are called too)
When you change  the BIOS settings, last,  those changes are made and saved and the Checksum ( as the name implies it adds up the bytes) and stores the checksum  summation in the same place. (for a later match up)
If you turn on the PC again and the checksum fails, that means NVram is scrambled, (called CMOS NVRAM or CMOS for short)  In all cases the silly RTC coin cell id dead, (  can fail as soon as 5 years old says "DuraCell(tm)"
NVRAM is Static RAM with a battery, forming a memory that does not forget,  until the battery dies, as all do ,and some as soon as 5 years old (seen one die in 1 year old, but was China 50cent knock off battery)
The word CMOS means the MEMORY cell is CMOS transistor based, a static memory it is,  deeply hidden in side all PC where no man can go or see, (deep inside the intel ICH9 is one example)
Not withstanding HPs horrid attempts to get UEFI working sure up date that if you must.
THE BIOS has 4 main JOBs:
 (when you turn on the Intel processor , yes that is what you do, it jumps to the BIOS base address , this is hard coded inside the CPU) then, it....
CPU automatically  jumps to main ROM memory address  0xFFFFFFF
Simple list first:
  • Checks for corruption of the RTC NVRAM CMOS memory for errors 99% of all BIOS issues, are here,  a simple dead RTC battery.
  • Runs POST tests, checks all the known to BIOS devices for present or not or showing errors from them. and report them to you.
  • It then collects this CHIP identification and stores it in the PnP memory location (plug and play for windows OS)
  • It then boots the first device in your boot order list.
  • The BIOS then turns over operational (executing code) to the OS. (called the OS boot strap, or as folks say booting up) The Boot code is on the HDD, a.k.a, Windows start up files.
A Detailed list of some important BIOS steps , it is sequential and linear in actions:  read this great flowchart., by Morris Rosenthal(©)
  1. BIOS in the old days was EPROM memory (UV erased first then burned in code) then later EEPROM and last off all today is  FLASH EEPROM (fast to burn "or program")
  2. BIOS reports PnP  information that can help drivers work faster and better as see here. PnP functions)
  3. If the PC BEEPS odd codes (or LED blink codes) the RTC battery is dead, if the code has any references at all to CMOS , NVRAM, CHECKUP or BIOS errors, Firmware, or the like. BINGO FOR  RTC BATTERY.
  4. If the screens is black? the RTC CMOS battery can be bad and only it, and is a super common failure. 
  5. HP  like others loved to change BIOS error codes every year 1985 to now, or near,  and is a pain in the ash can, this fact,  here is a 2005 old page from COMPAQ one of the worst ever made,  see code 9 , ouch.
  6. BIOS error codes were never standardized, and makes the old codes ARCANE to the nth degree today.  (the real pain of BIOS is here !!!)
  7. BIOS needs a working NVRAM or the PC is dead. (or acts wildly random) , So replace  the 3v coin cell battery now.
  8. If any PC will not boot the HDD (SSD) check boot order. now in the BIOS page called boot order.
  9. If the PC BIOS PAGES will not hold time of day or date or year,  again, bad RTC CMOS battery.
  10. I can tell BIOS (modern PC) to boot on the fly to anything I want using the power on and hammer the  F9, key.
  11. If booting to CD (any optical media )? learn about El Torito rules.  ( just hammer the space bar when booting to CD and it will boot. (if in fact disk  is good ,drive good and is bootable.)
  12. Easy reading?  El Torito spec, (Intel/MS/IBM)    boot to CDROM.    This allows say old XP to boot through the second time, and not do XP phase one installs over and over to the end of time.(getting nowhere)
  13. To learn your BIOS hot keys, RTM, read the manual , found at HP.com (or yours)  The service manuals cover this.  (F1, F10 ,ESC, F11 , F9)  My PC is ESC, 2009 forward for sure.
  14. Many PCs have a BIOS memory tests and a HDD test in BIOS.  Learn now to run that when problems arise.
  15. Many wrongly  think flashing a new BIOS every month is smart or wise, no, sorry it is WRONG,.   Here are the steps,  good luck wrecking your MOBO.! Good luck running any BRICKED PC.
  16. Learn to only flash to  newer BIOS , only if HP told you to do so AND, only if the new BIOS page (at HP) "details" lists a problem same as yours!. (for example added new processors, or one of the 10 bug fixes for UEFI)
  17. BIOS with  BIOS passwords turned on is a very bad Idea. Avoid this, or you may need HP direct intervention to cure it. (newer PC have this and no jumpers to bypass it ,by DESIGN)
  18. On new 2012 and newer PC, HP must have your UUID personal serial code to unlock you UEFI  if it is dead or passwords set.

BIOS IS DEAD SECTION here, just a list:  ( I can tell you it's not BIOS's fault it's not bad, It lasts for 100 years (a fact) please do not FLASH it) (flashing (verb) the flash EEPROM BIOS  chip, DO NOT DO IT.
If the PC ran new great, or ran for 5 or 10 years, why in the world blame BIOS for being bad, why,?  (most think it's a simple fix and then brick their PC)
The exception is HP PC 2012 early PCs with UEFI, and full of nasty bugs. (gee it's 2018 are not all those gone now, ?)
I can also say the CMOS battery is dead (RTC , RTC means real time clock and NVRAM battery coin cells are bad, even 5 years old)
The pre 2010 PC's  or monitors that can have CCFL lamps that go dead (yellow,dim,black,dead, or blink) that is tragic and near hopeless to fix. (read expensive)
If you think BIOS is dead, first do the flashlight test.
Most of these in the year 2018 are now all dead. (unless parked for 5+ years)

The blackscreen of death page  covers all black screen causes and tests you can do.  Do not flash your PC if the screen is black, do not or risk bricking the PC, and now it has 2 hard failures, is that fun?

Not to be confused with BLUE SCREENS OF DEATH.

LINKS to related topics on BIOS.
What can make BIOS fail or act strange or random? (besides BEEP and blink codes obvious) If it tells you CPU is bad, know that that is a big LIE. See #5 for why !
Did I say bad RTC coin cell enough yet?  1 million posts on line about this and not one mentioning this simple fix, (amazes me to no end) I guess $3 coin cell batteries scare folks?
  1. Bad main big laptop battery remove it first, or A.C. - Power pack is bad.  ( or Desktop PSU spec is here.)
  2.  (what is power, ?  see that AC wall power?, it is converted to DC power inside the PC, and the PC runs on DC power,  19vdc for a laptop and lower inside, hint, no power no joy, same with low power or noise there)
  3. if the PC fans are dead, there is no power (or is packed up solid in LINT , so clean it ?)
  4. The PC over heats and up to 3 major chips inside, CPU for sure shut down, they do that all by themselves , saving their own BACON. (the magic of Intel Inside ,ding ding)
  5. Bad Ram causes the CPU to malfuncition ( Just imagine you reading a book and someone, spills ink on all the pages, same deal, CHAOS) Test each memory stick 1 by 1, in bank 0 first. (or good /bad responses)
  6. Some PC desktops (Enterprise grade) defaults to  PXE NIC first,  and will not boot the HDD,  so turn it off, in BIOS.
  7. BIOS talks to the screen now, or the PC is dead and BIOS shows a text message to the screen, "Hit F10  (or ESC) to enter setup"  If not check for dead CCFL back lamps.
  8. If BIOS now jump (boot list)  to the HDD drive, you see the HDD fail to boot, then the HDD is bad, or the OS is corrupted, what then?
  9. Try the F11 Recovery key (2006 and newer PC) to restore the OS. (OS = Operating system ?ergo Windows bla bla) if you erased your HDD at anytime, F11 is now dead forever and you did that.( buy a new install disk)
  10. The OS then shows a login screen that must be presented and look ok, or the OS is bad. If you lost the password here is the fix.
Windows 10 has this nasty new feature. (like electric heated car seats )
By default it does not boot to clean code.  sorry, it boots to an echo of the last memory image,  to do the inane feature called fast boot. (for  lousy  2  seconds! gain !)

If the silly thing,  saves a bad image to the hiberfil.sys file,  the PC will not boot, again, until you read the simple fix below.
The F8 key was also deleted by MS, (why? only your deity  knows) but can be reached this way now.

Very Loosely related is W10 dead.(and this silly F8 key .

version 4.  5-9-2017