PC switches off - PSU still running

[Mantorok]

Hi all

EDIT:Guys I better mention this is an eMachines 8120!!

I have a 3-4 year old Pentium 4 2.8Ghz, 1Gb RAM, 160HDD and recently it's started to switch off instantly, usually within around 1-2 minutes of boot-up, the motherboard shuts off and the PSU continues to run - I have carried out the following checks:

~ Checked CPU HS & Fan - all fine
~ Taken out all devices (graphics etc.)
~ Swapped/re-seated RAM (have 2 chips so have tried each one individually)

Still got the problem, one thing to note is that the PC will only shutdown if the machine attempts to boot-up, if I leave it in BIOS it will sit there running fine, it only appears to shut-off when XP tries to startup and run, I can even get it running in Safe Mode for around 10-20 minutes before it shuts off again - so it would appear that it only shuts off when it's being "pushed".

I can't check the CPU temps from the BIOS but seeing as the fans are working fine I think that's OK, the only other thing I spotted upon close inspection last night was that one of the smaller capacitors on the motherboard looks slightly suspect (i.e. slightly expanded on top - although no leakage).

I'm going to try another PSU tonight to see if that's the problem.

Any ideas??
Thanks

 

[snyprozz04]

Dude, have you tried re-installing your operating system?

 

[Mantorok]

Dude, have you tried re-installing your operating system?

Yes, but it doesn't make it, it copies the setup files across then when it fires up windows it cuts out again.

 

[Rik]

Try a new psu. With an emachine psu of that age it's probably about to die any moment, and if it does, it's likely to take the mobo out with it too.


[edit]
Knowing first hand how crap emachine psu's are (especially if the label on the psu shows that it's a Bestec) I personally wouldn't risk powering it up again.

 

[Mantorok]

Try a new psu. With an emachine psu of that age it's probably about to die any moment, and if it does, it's likely to take the mobo out with it too.

So the mobo may be still ok? Should I replace the PSU if I do buy another mobo?

Kev