Here's the problem. I have been running a 3.2 P4, on a Asus P4S800 MB with a Gigabyte Radeon 9600 XT (GV-R96X128D), with 2 GIG of ram for 6 months now. It shut down fine yesterday and now will not boot. When powered up it starts the fans and nothing else happens. The monitor says it is OK but has no signal. I have replaced the video card with a know good one. That changed nothing. I have removed and reinstalled the ram. Nothing changed again. I manually opened the CD drive and tried restarting with the XP disk and the MB disk. The PC did not even try to read ether disk. One other thing. The power button on the PC is red and holding it in for 5 seconds will NOT shut down the PC. I have to turn the power off on the back of the PC to shut it down. Any and all help would be great. Thanks for your time in advance.

Here is an update on what I've tried. I discounted the CD drive, the Floppy drive and removed the Ram memory. All at different times to see any changes. The only change came with the CD drive removed and it was that the power switch light was no longer on red. It was not on at all. Next I removed the hard drive. The only thing this changed was the few sounds that the hard drive makes. Very light clicks. Next I replaced the CPU with 2+ Gig celeron. No change. Someone please help or shoot me. I'm going nuts over this.

do you get any beeps from the PC?

No beeps at all. Just the fans come on and the hard drive makes it's normal soft clicks. The MB has a power light on it that comes on to. The video card has a light and a fan that comes on. The CPU fan and case fan come on. The two fans on the power supply comes on. No sounds of hits on the CD or floppy drives.

you should get at least 1 beep to say the machine has completed post, try removing everything from the motherboard except for the cpu and heatsink/fan.

try all your connections.

Removed everything from MB. Still no Beeps. CPU fan comes on. Power supply fans come on and that's it. Oh and the light on the MB comes on too.

Here is another update. I tried another power supply. No change. Help!! What else can I try?

by the sound of things it looks like your motherboard has gone.