lau wrote:
Just one minor thought... if the fan indeed is NOT rotating, conceivably the wire has just dropped off (or the contacts in the plug/socket have just become corroded).
PS. In a well-designed case, with working fans, taking the sides off will NOT improve airflow.
Yes, but well designed is often not the OEM specialty

Now, if this is a NICE clone, then obviously you've got something more than a little problem.
Another thing to think about. Whats the average air temprature of the room the computer is in? Computers are happiest when rooms are around 50 or 60 degrees, although most people caint tolerate that. If your room is often in the 80 or 90 range, then the computer is going to be even hotter. Try keeping it about 70 or 72 if it must be warm.
Use a vacuum to suck most of the dust bunnies out of the computer. If you need to, remove the heatsink and fan and rinse them under some water, but MAKE SURE it's dry before you put it back. You'd need to get some thermal compound to do this, but dirt and crap around the fins of the heatsink will really kill the cooling abilities.
Another tip: DON'T SMOKE AROUND THE COMPUTER!! ! I'm not saying you do, but, if you do, that tar stays tacky and gets into everything, and I mean EVERYTHING. I've found the tar has eaten away AS5 and made chips overheat. It eats fans too, badly.