Why won't my iMac to boot up?

Episode 1090 (2:24:07)

Jim from Harbor City, CA

Jim is having boot problems with his iMac running Snow Leopard. It's constantly telling him to restart. He can't boot from a startup disk. Leo says it sounds like a Kernel Panic. It means that the computer just can't go on. So that means that there's a serious issue with the hardware. Jim can try zapping the PRAM by rebooting and holding down CMD-OPT-P-R. Sometimes that'll solve it. But it's more likely a logic board problem or a power supply.