Hi, can anyone tell me which fan is the 'system fan' on a compaq presario? I don't know the model number off the top of my head unfortunately, I'm going to try to find the receipt tomorrow, but it's about 1 year old with duo processors and vista. When I turn it on now it says system fan failure, please service pc to prevent damage, but the power, case and cpu fan are all working. The cpu fan looks like it isn't running quite as fast as the case fan, but I've never really watched it before so I don't know how fast it's supposed to run. Any help or advice anyone could offer on this would be appreciated. If I can find out which fan it's talking about I can get another one and change it over. Thanks, Mike