I'm having a strange issue with a DP450 Mac G4. When you press the power button it lights up but the computer itself won't power up. The machine was working fine about 2 weeks ago after I had changed out the stock DVD ROM with a 4x burner and added a SATA controller and a 400 gig drive. The machine had been off while I was out of town for turkey day. Does this sound to you like a power supply problem that could have been caused by a power surge or did I personally drive nails into this poor machines coffin?