How old is this computer? Make sure the power supply fan is working by 
observing it when you power up. You can usually tell if it's working 
properly by turning it with a pencil or something similar-resistance 
should be very light. Same with the CPU fan.
I'd test the power supply by disconnecting all CD drives and maybe one
of the fans and then see if it will power up. If a reduced power load
doesn't help, start removing cards , including memory, (especially) one
at a time until you can boot.
I assume the case looks relatively dust free inside.
You can get a power supply tester for about $10.00


MICHAEL CAMPOBASS0 wrote:
> Hello ... First time writing ... wonderful place for computer help. I
> have a computer with a problem ... it wont turn on or more precisely
> wont stay on ... it shuts off (by itself) after 2 seconds or so ... 
> ---  Pentium 4 ---  1 Gig memory ---  Running Win XP Home edition ---
> Mother Board is ASUS P4PE-X ---  2 CD drivers (1 Burner and 1 DVD
> player) ---  A floppy driver ---  Connect to Internet using a DSL
> access ---  ATX Case with 2 Cooling fans besides the CPU fan and PS
> fan ---  300 watts Power supply ---  McAfee A/V software Here are the
> specifics: The computer is well maintained ... Using Anty-spyware
> cleaners and Virus scans ... the computer is also updates as
> required. I had turned it off for the night ... the next morning when
> I attempted to turn it on it seemed that all was ok ... heard the
> fans surge, the power-on light on the front of the case lighted
> normally ... but after 2 seconds the computer turns off (the power
> light remains on). I have to keep the the front power switch pushed
> for about 5 seconds to turn the light off so I can truy again. I dont
> hear any beeps. Opened the case ... tried to power it ... noticed
> that all the fans operate also there is a green LED on the MOBO that
> is always on as long the Main switch on the back of the case is in
> the on postion. I disconnected one drive at the time and power it ...
> but no luck. Could it be a defective power supply? Or a dead HD? It
> was working fine the day before ... I dont know how to check it if I
> cant turn it on. Does anyone have a suggestion what could be the
> cause of this problems?. Any suggestion will be appreciated ... Thank
> you so much Michael Campobasso
> 
> 
> 
> Michael

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