1. buy an air duster.
2. take panel off of your computer tower.
3. air dust everything.
While your panel is open, check to see if all 6 or seven of your fans are working properly. If it is overheating, which can or cannot be the problem, you should cure or find the problem relatively fast if you pull the panel off, dust everything, and do a quick visual check of the fans. Other ways to tell if its overheating is note the air in the area that your comp. resides. The intake takes in the surrounding air. Is your house or apartment hot? Live upstairs? Got an air conditioner? Are you farting into the fans? lol - I've also heard that smoking near your computer alot can clog vents and fans with tons more dust and ash than normal causing it to clog quickly.
Maybe they should start installing cooling mechanisms into computers...