Compaq Presario S3000NX Not Powering On

I've got a Compaq Presario S3000NX that refuses to turn on. The power supply has been checked. The fan doesn't try when I attempt to power it on. The light beneath the power plug in on the back of the tower blinks green even when not connected to the power source (at a slower rate when not connected but still blinking nonetheless).

Any ideas?

Thanks~

 

EDIT: After several minutes disconnected from a power source the green blinking did stop.

 

I did to no avail.

 

Maybe try the troubleshooting steps here http://h10025.www1.hp.com/ewfrf/wc/...06788&dlc=en&lc=en&jumpid=reg_R1002_USEN#N207

I don't understand this hairdryer trick but it looks like you just blow a hairdryer at the back of the power supply for a minute or two and see if the light turns solid green again. It makes no sense and since you have already tried replacing the power supply it makes even less sense. I am just posting it because I have seen it several times for HP power supplies. http://talk19.wordpress.com/2008/01/13/hp-m7088d-power-supply-led-blinks-green/

 

I had a similar problem. Not sure if it was the PSU (a Bestec model), but I replaced it anyway (with an Octigen PSU that had an on/off switch but no LED, not a precise fit to hole in the case, although both were ATX). Later I began to beleive it wasn't the PSU, but possibly the CPU fan ?? Problem appeared to be solved, but something is now still wrong...however PSU light doesn't blink anymore (for the reason given above...)

Dumb_Question
12.January.2012
Compaq Presario S5160UK (Celeron 2.7GHz) - MSI MS6577 v2.1 - XP SP3

Note : most HP computers use OEM PSUs.