pc reboot loop

[metalmachinist]

Friend's PC stuck in reboot loop.
Windows 8. yesterday it started by restarting whenever he tried to play gw2 or other games. today, when he first turned it on, went to a blue screen that says windows encountered a problem or something like that. then reboots, then goes back to same blue screen, then over and over again. wondering if it's and OS problem or hardware temp, or PSU problem.
Specs are:
amd fx6300 on gigabyte ds9 mobo i think.
gtx 460
8gb 2x4 1600mhz ram
2 year old 600w thermaltake psu

also, he runs advanced system care everynight before shutting down, which cleans registry every day, could be messing up the OS possibly?

Need help please

 

[i7Baby]

Start in Safe Mode - F8 http://windows.microsoft.com/en-au/windows/start-computer-safe-mode#start-computer-safe-mode=windows-7
then Disable automatic restart on failure - http://windows.microsoft.com/en-au/windows/advanced-startup-options-including-safe-mode#1TC=windows-7

Then you need to sort out the failure -

Post your complete and detailed build.

Download HWInfo and run Sensors. Post the results - usually 3 screenshots in TinyPic or similar.

 

[metalmachinist]

PC won't even turn on any more. but keyboard is lit up and other usb devices work, weird

 

[i7Baby]

Go thru Tom's checklist then - http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems