Hi all got a Imac 8.1 20 inch running snow leopard and my cpu fan is running flat out all the time,i got smc fan on default and done all the other resets to no luck was going to try hardware test but no luck with that as got no disk for it and not on hard drive.If anyone knows how to do the test or where to download it from or a another program that does the same thing let me know thanks.