Not the primary computer, but one I have sitting in the living room for random internet use, etc. Would be sad to lose it, even though it's certainly not the newest thing around. I have an iMac G5 running leopard. It's remarkably fast with 4 gb of ram. Certainly no speed demon, but it's fast enough to not be annoying (primary computer is a new iMac and new MBA). Anyway, all has been well for the last 6 years or so, but randomly last week it started going to sleep when ANY sort of significant load is placed upon it-- file copy, flash video, etc. After searching around the internet a bit, it seems pretty likely that it's overheating and going to sleep to protect itself. Which leads me to believe that one of the fans have failed. Cracking it open, there's 3 different fans inside. It seems unlikely that all of them have failed, and I'd rather not buy all three to replace one bad one. Any tips on how to diagnose which fan is the failed fan? Thanks!