|Overheating is the probable cause but it could also be a memory or driver issue. If you haven't already done so, turn off "automatically restart"...that way instead of rebooting, a blue screen will be displayed with an error message that will help you to troubleshoot the problem.|
- right-click My Computer, then click Properties.
- click the Advanced tab.
- under Startup and Recovery, click the Settings button to open the Startup and Recovery box.
- under System Failure, uncheck the box next to Automatically Restart, click OK, then OK again.
- restart your computer