Please let us know your hardware and model numbers.
Also please upload the latest crash.
We need those hardware model numbers to help you otherwise we are guessing.
Also, just to be sure have you:
1/ Run offline virus scan
http://windows.microsoft.com/en-US/w...fender-offline
2/ Run a RAM test
Memtest86+ Memory Testing
3/ What anti virus / malware software are you using?