Windows is now Dead or SICK?                              
                   We call this the  OS, for Operating System.

Given: The PC hardware is not dead, the Hard disk is not dead, the screen is not dead, just windows is dead, corrupted or infected. 
In all cases we first test fully the HDD, (if SSD?, it usually will not fail)  We run Chrystaldiskinfo (free) tests  or run Ubuntu v17, disktest.(parameter 198. must be zero of not , bad hdd you have.)
There many ways to recover a windows that is corrupted.    (do not confuse , black screens of death as being windows corruption.
This page below is not for DIM screens (or yellow bad CCFL or dead screens or dead monitors)

The answer is based on the year the PC was made. (in all cases this is so very true)
Old PCs from about 2007 or older do not have the recovery partition built in the HDD,  (think that as built in virtual CD install disk from the PC maker ) The old PCs you must have or buy new install media.
When I say install media that can be optical disks, CD/DVD/BR or USB thumb drives (ISO loaded) or even SD memory devices.
The F11 key on HP is the magic recovery back to day 1 new, and all your data and apps missing.
But first things first is called HOPE, we test the HDD and it passes, if lucky W10 still runs, it is not dead yet(w10 is all I cover,) we run SFC first then DISM.
We always test the HDD /SSD main disk drive first or this can be endless pain.
If the PC is virus infected, (malware) in almost all cases you will not ever get rid of  virus by trying to clean it out. (this is what happens)
I consider the OS the same as old dirty socks when soiled change them out, ( washing them may only get some dirt out, if you get my drift?)  The fastest cure is reload the OS, F11 or from media.
If still running XP or Vista, get rid of this junk, XP is virus magnet.
PCs are complex both the hardware and the software, but we test the hardware first, after all if it is bad, how can software work right? (answer It can not)
We by fresh new batteries, RTC coin cell at 5 to 7 years old, and if a notebook/laptop the main battery is now useless or worse shorted, just remove this large battery and run on AC power pack forever, or buy a new one.
The HDD is #3 failure device, as soon as 5 years old or dropped running.

Solutions, tests and ways to recover Windows 10, (my HP with W8 had free update to 10 home)
If the OS runs mostly , but has problems, the operator can do a windows, go back to a previous restore point , as seen here, step by step.
Next would be the SFC repair.
If W10 is totally dead, no  login, or fails to reach desktop?
Kill fast boot, now:
If Windows 10 will not boot , turn off Fast boot.
HP centric, all my pages are that, but most major makers have  BIOS HOT key for OS recovery,  HP uses F11, this key hammered at power on launches the RECOVER  PARTITION Recovery.
Read you manual on your exact PC at your PC makers web site, first. So see what HOT keys your maker uses. (DELL  is F8)
YOU now go back to day 1 factory fresh PC with , all data you created (and Apps) are all gone.
If the HDD is bad F11 will be dead, if the drive was changed out before,  the HP recovery partition is now missing and F11 goes dead.
If virus infected, the virus might in fact infect all partitions on the HDD or far worse, all R/W media in the PC, be that SSD, HDD, or M.2 media.
HP F11 feature started about 2007 year, before that year the OEM sold install CDs (or DVD),called OS recovery media.
Or your other choice would be buy a new OS from Microsoft or load Ubuntu v17 for free.

A list of steps?
F11 recovery will be dead and gone if you replaced the HDD ,or  with SSD. (or upgraded the OS) I call this case slammed)

Here is the HP F11 page on topic.  (as HP shows  you online, about this topic)
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Windows is either corrupted or dead when: ( hardware all tests good , OK? HDD good, monitor is good, BIOS works and the PC runs Demo disk running Ubuntu try me.)
  1. You can't reach the login screen for windows. (lost the password is not windows is dead)
  2. Some PCs beep (old skool) or beeps for blinks flashing the CAP's lock key, are not to be ignored, but one code can be I CANT boot and that is our topic or does boot but is corrupted OS.
  3. If w10 is totally dead, do this, Shut  off  fastboot feature
  4. If w10 still dead, do F11 Recovery now, back up data first.
  5. If the PC shows signs of INFECTION, only F11 is the cure, (or fresh loading w10 from media, you build)
  6. The Desktop shows up,  and the CMD.exe prompt works. (run box, type cmd,  then right click it and pick run as Admin.)  If this works you can next run repair 
  7. We get this far, but windows runs, but is stick so we do SFC and DISM. (do as MS stays not others, note the ISO disk present)
  8. Some PCs need to have the above line run 2 times or more to cure Windows.
  9. The control panel in Windows is dead, it's infected. Same with device manager dead, or the programs add removal pages in the control panel are dead. (INFECTED)
  10. And vast other odd bad things seen in windows, the effects of corruptions are infinite.!
  11. Running XP or Vista,  buy and install W7 or better W10.
F11 is the most easy solution,  works only if the HDD/SSD is good (tested here), and the F11 HP partitions are not slammed.
On only new PCs, HP has media kits.  (In most cases after your PC dies, F11 goes dead or HDD dies, the below media is no longer sold, nice huh? (sarc off)
Then go to HP.com and get your MEDIA KIT.

 DO NOT LOSE DATA:
In call cases backup data first, there are ways to do this if the HDD is not dead.

You may need to drag the HDD to a good PC and back up that way. (our boot to linux demo mode)
There are many ways to backup data , if you don't own or run a backup server or use THE CLOUD. (the external say 2 TB drive)
There is never a reason to lose data. Just backup often. (or use the silly Cloud and pray it works)
Never use Microsoft backup ever it is lame and weak, (or as I call it cripple ware)
I use "EaseUS Todo Backup Free v11" this is not the only good BU program, but works very well, I can later recover 1 file, easy, not have to recover all files or some other crazy limits.
You can google for that EaseUS, company.

Upgrades to W10 are possible, 32bit may work on PCs 10 years old or  older but not XP PCs from 2001 , ever. (the reason is simple most XP chip driver makers are now dead, gone or moved ON)
The W10 64-bit is a tad tricky and for sure fresh clean loads are the most strict,  Intel Gen6 or newer processors, strict, Gen 5 for upgrades say W7 to w10 64bit. (i7-6xxx means gen 6)
What I do is buy  a 8GB USB thumb drive, and get the ISO from Microsoft, and use RUFUS to burn the stick with the ISO image. (Microsoft as USB stick maker to but I like keeping the ISO , on my server)
Then boot the USB, but on modern PCs,  for sure w8 and newer.
UEFI is not the same as old loved BIOS:
Welcome to UEFI BIOS, (my desktop runs CSM BIOS that is both BIOS and UEFI dual mode (ASUS) .
To boot to USB (or DVD) you must turn off Secure boot and turn on Legacy Support. This is a HP PC.(modern )
When you do that the UEFI sends you  a secret 4 digit code (this blocks viruses this trick) You then reboot the PC.
The PC tells you,  omg UEFI security is breached, and asks for the secret code, and then you type it, 1234 and does not echo to the screen do not panic, just type it blind and hit enter.
If you back this page in UEFI, you see the below locked in. I like to put the USB/KEY as 1st boot order.
But you can now boot and hammer the F9 key (this is HP boot on the fly key) and then pick USB key or DVD. as the case may be. and even load LINUX.


 
Windows 10 on the HDD, is about 17GBytes in size now

To see what 10 build you have ,  run and elevated command prompt, (cmd.exe) and type WINVER (enter) Shows version and build #

Windows 10 can fail easy,  it boot today using fastboot from hiberfil.sys  and the cure is here if failed.

This will be you  if you install any OS onto a bad HDD, weak or bad, or has bad clusters. (endless pain) the same is true trying to run virus cleaners after the fact (infected)




version 3.  12-9-2017