A customer brought in a black MacBook Core Duo 2.0GHz for a hard drive replacement and reinstall of Snow Leopard. Installed the OS and all updates, now the machine has suddenly developed a shutoff problem. I've been able to use it for maybe 2 minutes at most since she brought it back to the shop, and once or twice it even shut off during bootup. My first thought was that it might need the SMC Firmware update that addressed a similar problem, but the computer says it doesn't need the update. Reset the PRAM and SMU with no success.