IBM won't move past POST

Actually, I'm not sure if it even goes through POST

I have an IBM Netvista machine, P4, 1.8Ghz, 512 Meg, 40GB HDD, Win XPP

Normally when I start the machine I get high revolution fans for a couple of seconds during POST and then they slow down and Windows starts.

Lately when it is started the computer won't move past POST. The fans spin at the higher speed and nothing happens. I don't see anything on screen. If I unplug the machine from teh wall it restarts normally.

I changed the PSU, display adapter, updated the BIOS, swapped the HDD with another from an identical machine, there are no leaking capacitors, the memory and HDD test OK.

Any suggestions on what I might look at next?

Thanks

 

Faulty power button?

It's possible that the system is set to restart on power failure (in which case you don't need to use the power button).

Have you tried powering the system down using that (press and hold for 4-5 seconds) and if so does it work?

Ignore my post, obviously the power button is functional

 

After much thought I tried changing the memory module (I had only tested it before) and the problem has seemigly been resolved.

Go figure...

Thanks for the reply though