Crashes running video programs

My computer has been freezing and randomly rebooting lately. I haven't installed any new programs or drives, and the reboot generally comes when I try to play a movie (in any program from Windows Media to DivX) or music in win amp, or mapping programs like google earth. I tried to repair my boot sector, did all the virus and spyware scans the computer recommends, and updated my windows file. I have tried system restores but for some reason the restores more than 3 or 4 days old fail, and the restores from 1 or 2 days before the problems started occuring don't fix the problem. After a google search I have found many people with the same problem, few solutions. One person suggested that it may just be too dusty and over heating. How do we check the temperature? I will be cleaning it out today, but the fan is only about 6 months old, so I'm no sure that's the problem. Anyone else have ideas?

 

A few pc specs OS mem cpu etc.... Will help us help you
Do you have a OS(cd) for your pc
Dusty and overheating 6 months old .. It is possible for a pc to gather all sorts of things quickly if used in a high stress enviro (sitting on the floor in a corner, near a window or a door)


cleanitcarefullyandletusknow!