Recently my main comp has had issues with starting up. I press the power button , the hard drive LIGHT comes on for a few seconds , then extinguishes. Normally there's additional activity as it boots. The monitor light goes to amber , the power light remains on. I run two comps on a KVM switch. I've tried to GET into BIOS and safe mode , with no results . I did get it to start once , and it was fine while it was on , but this last time it just quit after a few minutes and I couldn't get it back.
This is what I've tried so far : Disconnected main from kvm setup , removed graphics card , checked to see if power supply fan is working , processor and case fan clean and ok , ran updated virus and spyware software last time I had it going , made sure no disks in drives , removed modem card , tried STARTUP with monitor disconnected.
The only thing I haven't done is remove the additional memory I added when I GOT the machine. The other machine acts normally unless I switch the KVM over to the afflicted machine , then I cannot switch back over.

It's an HP a832n 3.2GHz 2 GHz RAM Pentium 4 .

Please helpSwap in a known working PSU of the same or greater wattage...REPLACED the 300W unit with a 400W , aside from making an extra trip to get the 24 to 20 pin mobo plug adapter , so far so good . Thanks much for the suggestion . I'm crossing my fingers.Glad to hear it worked out for you..stop by anytime.