Nothing can put a damper on productivity quite like a computer that crashes on a regular basis. Sometimes, a crash is preceded by the dreaded “blue screen of death” or another warning; other times, a computer simply shuts off without any warning at all. In either case, the end result is a whole lot of frustration, aggravation and lost work. If your computer has been crashing frequently, you’d probably like to put an end to it. Unfortunately, getting to the bottom of things if often easier said than done. The following tips about improving your computer’s performance, though, are excellent places to begin.
Possibility #1: Corrupted System Registry Files
Every Windows-based PC has something called a Windows registry. The registry contains several files that are integral to the performance and operation of your computer. Over time, some of those files can become corrupted, be misplaced or get lost altogether. When that happens, the system registry becomes compromised – and frequent crashes are all-too-common symptoms. The best way to rule this possibility in or out is by running a Windows registry cleaning program. Such programs scan your Windows registry for problems then automatically make repairs. If you run a registry cleaner and the crashes persist, they are probably being caused by a different issue.
source:
http://www.computertips.com/pc-troubleshooting/