Do a search online, and you’ll find plenty of power supply problems on Dell Dimension 4600 model. I’ve been lucky to have my Dell running fine for 3 and 1/2 years, but finally the power supply bit the dust last week. I was hoping that I can wait for the new iMac to come out, but I really want Leopard so I bought a refurbished power supply from Dell. The old one was revision A00 made in Thailand. The refurbished one is revision A05 made in China.
Dell Dimension 4600 power supply