|Either the power supply is bad, or the power circuitry on the motherboard is going. This is definitely not a HDD problem, and probably not video related.|
-Hook up a power supply that you know is in good shape and run the computer for a few hours. If it doesn't boot, you probably have a bad motherboard.
-Check for leaking/bulging capacitors on the motherboard.
HTPC | Pentium M @ 2.82GHz, 2MB L2) | 4GB | 1.0TB | Radeon HD5750 | Blu-Ray
Win 7 Pro | HDMI out to Onkyo TX-SR707 receiver & Samsung Series 5/63"