Have an Acer Aspire 5750G, power it on, I can see it POST's, then powers off. This is what I've tried so far;

Removed battery and ran off A/C - same
Removed battery and ran off A/C, reseated memory - same
Removed battery and ran off A/C, reseated memory/placed into different module - same
Removed battery and ran off A/C, removed hard drive - same
Removed battery and ran off A/C, reseated hard drive -same

Any other ideas? Power lasts for 2-4 seconds.