you shouldn't have to worry about your CPU overheating unless it starts hitting 60+ degrees celsius (
http://www.hardwaresecrets.com/artic...perature/143/5). GPU's are generally tougher, with any modern video card you should only worry if the temp spikes above 90C, a card idling at 50-60C is quite normal
also the FIRST thing you should do is disable Windows from auto-rebooting when it encounters a critical error. if you right-click on My Computer, hit properties, then look for Advanced System Settings, you'll see an area called Startup and Recovery. go in there and under System Failure uncheck the Automatically Restart option. now instead of rebooting your system will give the classic Blue Screen of Death. you won't have any choice but to still reboot the system, but at least now it will give you an error code and you can pinpoint exactly what's causing the problem. if you write down what that error tells you and post it here, it shouldn't be too hard to trace the problem