Windows 10: PC crashing and rebooting to previous state

My computer has been crashing at random for about a week now, and when it reboots it restores the settings, programs, and files as they were before the first crash. It's made it impossible to reliably use. Everything will run fine for an indeterminate amount of time I'm writing this on the computer in question, and have played games and browsed the internet for hours before programs stop being able to open, the screen freezes, and it either goes straight to black or a BSOD with SYSTEM_SERVICE _EXCEPTION as the cause. Programs can be installed or uninstalled and settings can be changed, altho

:)

 

all games crash!

ive watch my temps and both the cpu and gpu are within normal ranges. when it freezes it simply freezes the image and stops the sound. i must reboot to get back to windows.

 

PC reboots (no BSOD) on CPU stress

Hi fellow TPU members,

not too long ago, the box my gf's PC was transported in gave way on the stairs. Yes, you got it right, that sent a PC tumbling down a flight of steps alright.

Stuff broke. Also, stuff remained intact somehow.

I bought her a new case, new CPU cooler and we removed the floppy drive, so far so good. But the PC started crashing for no apparent reason, without a BSOD.

I tested:

• Memtest86+, left overnight, 0 errors
• Scanned the HDD for errors, nothing there
• Left FurMark burning up the GFX card and drawing some power, no problems there
• Ran Ubuntu from a Live CD doing nothing special, didn't crash
• Ran OCCT, Linpack, Prime95, all 3 caused reboots within minutes
• Oh, and I disabled "Restart on error" so I'm sure it's not a BSOD.

Now, I can still try and test something CPU intensive on Ubuntu, but my guess is the CPU didn't survive.
Before I do anything drastic like whippin' out the magic wallet and get her a new AMD quad, is there anything I didn't see?
I'm guessing the motherboard could be borkered as well, but can I check that other than replacing the CPU with a working one?
Any suggestions on which proggies I can use from an Ubuntu Live CD to stress the CPU?

 

all games crash!

I suggest you run rthdribl > http://www.daionet.gr.jp/~masa/archives/rthdribl_1_2.zip
Increase the window size step by step and watch your vga temps permanently.
What happens?
If it crashes, run at stock speeds as suggested before and retry.

P.S.: When your system locks, does the display signal turn off after a time?
Stuttering sound or no sound at all when freezing?
What X1800XT model do you own exactly?