Ok... so a friend of mine is having problems with their 2.16 20inch Core 2 Duo iMac... The computer chimes on and stays on for a while. Has been doing this for the last few weeks, they had Tiger on it. They were able to load Leopard 10.5 on it (thinking a reinstall might help, and they were going to upgrade anyway), but it still restarts after a short time randomly. Sometimes it will run for an hour or so even but still randomly restart, it doesn't shut down, just restarts. Does anyone have any suggestions on how to fix this and what might be wrong? It runs ok when it's on, but will just randomly restart, and it's not always the same time frame or same action that does it. Completely random it seems. Should there be something changed in the system itself? Logic board? (hope not!) pram issues? Any help is appreciated. A step by step process for something would be good too so I can just pass it along to my friend who isn't super well versed in macs yet Thanks in advance!