A few weeks ago my Windows 10 PC crashed. BSOD. and hasn't been the same since.

An error appears just after Windows loads: "C:\Windows\System32\Windows.System.Diagnostics.PlatformTelemetryClient.dll is
either not designed to run on windows or it contains an error etc...."
(see 1ps.jpg attached)

Also, weirdly, when you press the windows button on the screen or keyboard, no programs are shown
(see 5ps.jpg)

I can't run programs like Word, or most of the other programs I've installed. VLC and Firefox still work oddly.

I can't install or run Windows defender or CC Cleaner or simlar programs
I don't think it' a physical hard disk problem. I don't think it's necessarily a virus or malware problem.
I think the registry has corrupted itself.

I successfully cloned the drive to another physically "known good" drive, so I can mess with the software on this clone without worrying.
I can get the PC to go into safe mode by holding down left shift key, right clicking start button (as left clicking Start doesn't work!!!) -> Shut down or restart -> restart

”System Restore” - no restore points have been created on your computer’s system drive.
“System image image recovery” - Windows cannot find a system image on this computer.
“Startup Repair” - Startup repair couldn’t repair your pc.

I got to the command prompt
"sfc /scannow" completes with no errors reported

I tried to create a different user account, but get the error
"the user was successfully created but could not be added to the USERS local group

I ran regedit and saw something weird.
The program files directories are shown as the X:\ drive
Sure enough, so is command prompt X:\Windows\System32

see attached photo.

Like most people - this should be my C:\ drive.
I have no idea how this happened. Malware perhaps - or just Something that Windows 10 has done to itself.

Either way, has anyone experienced this or know of a way to fix it?

Thanks!Click image for larger version. 

Name:	1ps.jpg 
Views:	1 
Size:	402.9 KB 
ID:	180408Click image for larger version. 

Name:	3ps.jpg 
Views:	1 
Size:	284.2 KB 
ID:	180409Click image for larger version. 

Name:	safe_mode.jpg 
Views:	1 
Size:	1.63 MB 
ID:	180410