P4 system doesn't POST

[Phaelax]

It's an old system of mine I haven't used in a few years. It worked fine when I stuck in the closet, but now it's being weird. Sometimes I could make it into Windows but then it'd crash; BSOD. So I threw it back into the closet for another 6 months. Tonight I was looking at it, thinking maybe the capacitors blew. None looked popped as far as I could tell, but I notice the 4-pin power wasn't plugged in. Thinking maybe I had an insufficient power issue earlier, I connected it and booted the system. XP began to load, getting past the boot screen and onto loading Windows. But before it could finish, BSOD. I tried it 3 times and crashed in same place each time. So maybe the install was hosed. I swapped harddrives, nothing. I put the old drive back in, still nothing. Machine won't even POST.

Asus P4P-800E Deluxe
Pentium 4 2.8e (prescott)
2x512GB DDR400 (Crucial I think, copper heat sinks on them)
Gigabyte 128mb GeForce FX5900
WD 80GB
Antec 430w psu
no cd-rom is connected right now

I'm cleaning any dust out of the case and reseating everything, but I have a feeling that won't make much difference.

[Phaelax]

Also wanted to mention, there are no system beeps when I turn it on and no lights flash on the keyboard as it normally would. But the power does come on, fans spin up.

[jak0b]

Electrolytic capacitors dry out with old age, they don't blow :)

All PSU's will loose capacity in time due to this fact, even if you stick it in a closet, just not as fast as if it were plugged in and in use (a matter of temperature).
On average, PSU's will loose 10-15% power each year, so your 430W Antec will provide 190W-280W after 5 years

I suspect you PSU is getting too old, and even if the PSU-fan spins up (only 100-250mA), it probably just can't handle the system anymore.

You can try this calculator to see what is recommended as a minimum: http://www.coolermaster.com/support/psu_calculator.php