|It can be caused by broken, disconnected, or misconfigured hardware, OR overheated hardware, OR a problem with an important part of the operating system, OR some other misconfigured software, OR the result of malware.|
It's really important to get the full error code that flashes on the screen before the computer reboots, assuming the computer didn't reboot as the result of overheating. You can also check the System tab of Event Viewer (Start > Run > type: eventvwr.msc) for items with warning signs.
In addition, you can configure your computer NOT to automatically restart on a system failure so that you can view the whole error message. Read this article to learn how: http://www.computertechtips.net/28/...
Lastly, report details of when this first started occurring and any software/hardware changes you made around the time the problem first started.
Apologies if I don't respond to your reply immediately. I don't check this site daily, but you're welcome to PM me as a reminder.