I agree with garth, there are many possible reasons for this sort of problem and I would consider them before blaming malware:
- CPU problem seems most likely
- other system board problem
- faulty memory
- corrupted or faulty disk - can be caused by the others
Your options for resolving this are affected by which version of Windows you are running.
First, I'd check the condition of files on your disk and try to get a backup of your documents and data files. If Windows is corrupted then you have a difficult job.
http://www.sevenforums.com/tutorials...e-checker.html
http://www.sevenforums.com/tutorials...isk-check.html