My computer starts up fine and passes POST and I can access BIOS then load Windows but after a few seconds on the login screen or after I have logged in it reboots without any error message showing except if I manage to login and my startup programs try to start in which case I can catch a glimpse of some error message before the PC reboots. No bluescreen or anything else that indicates that something went wrong. I should mention that this is what I've achieved after using only one RAM stick since I normally use two but if I do that I my mem_ok LED starts glowing and pressing it doesn't fix it, it just continues to loop. Booting in safe mode still causes it to reboot after a few seconds after loading Windows. Clearing the CMOS changed nothing.
Specs:
Motherboard: Asus Sabertooth p67
CPU: Intel i5 2500k
RAM: Corsair Vengeance 2x4GB
GPU: MSi GeForce GTX 780 TwinFrozr
PSU: Corsair TX 750 Bronze
SSD: Corsair Force GT 120GB
HDD: Western Digital Caviar Black 1TB
Specs:
Motherboard: Asus Sabertooth p67
CPU: Intel i5 2500k
RAM: Corsair Vengeance 2x4GB
GPU: MSi GeForce GTX 780 TwinFrozr
PSU: Corsair TX 750 Bronze
SSD: Corsair Force GT 120GB
HDD: Western Digital Caviar Black 1TB