Im using linux, about week+ ago I got kernel panics on a daily basis. I switched to windows and on windows had random reboots. I then replaced the CPU heatsink cause I suspected it was cpu overheat. Problems were not solved, so I replaced a PSU cause a DMM gave me around 11.2V on +12V rail. This didnt help. Now after pretty long time the computers is off (a night usually, but I experienced it also after 2hours+), during boot on linux I get kernel panic of machine check exception and windows simply reboots. It goes like this: I select the os I want to boot (windows xp sp3) then it might restart straight after my selection, or I can see the windows logo and bar loading a bit and then restart. It might take 1-3 (maybe more) restart till I am able to load windows. During the usage its pretty stable (no random crashes). I disabled auto restart on failure, and it still restarts, no BSOD not minidumps no event logs. Memtest86+ for 12hours shows no error in 22 passes. OCCT full test on cpu, gpu and PSU for hour-two each shows no errors.
boot into safe mode and run "msconfig" from there you can disable all startup items, which should allow you to boot normally
most likely one of them is your issue so re-enable them one by one till you find the problem
Ill try it, but this is not the problem, Im sure 99% Since I got similar issue in linux.
My theory is if it works fine in safemode then the hardware is good, which is supported by you testing the mem and cpu already with no issues, so perhaps something you are running in both linux and widnows that is the issue.