Diagnosis on P3 733MHz

My desktop at work is a P3 733MHz (IBM) and today Friday 13th! it starting to go screwy - with random reboots and error messages mentioning something like 00000006 Trap! A couple of time I managed to get it restarted but most of the time it kept looping back to rebooting during windows 2000 start up. Now when I try and boot all that happens is that the cdrom drive whirrs and lights up and the power on light comes on but nothing else (no floppy drive light up or whirring or hard drive) and the monitor stays on the orange stand by light. As the CDROM is ok I am thinking it is not the mobo and thinking maybe the cpu has packed up. Anyone have any ideas as to what it might be? TIA.

I should also add that I have had it for over 3 years old and the only replacement it has had is a new hard drive about 6 months ago.

It might also be your memory crapping out. Can you boot with a DOS disk, and run memtest?

It sounds like the (U)PS has problems properly powering the PC up. My desktop has that problem once in a while, especially if I shut down the Line Filter unit for the weekend. My solution is to turn everything off (line filter, power switch on the back) and on again and turning on the monitor only after the PC starts it's first boot beep. That always does the trick for me.

I cant get into dos because floppy is not functional (only cdrom starts up) as for UPS system wouldnt that just be a complete go/nogo scenario if it was a problem - the power up light comes on and cdrom whirrs so some power must be getting to the system. One thing I forgot to mention (which is probably pretty important!) is that I do not get any beeps whatsoever.

Your floppy is not functional? Then it is no wonder Win2000 won't start..... Did you check for loose cables? Reset the CMOS?

Checked for loose cables and also reset the CMOS although I probably only took out the battery for 10 seconds - should it be longer?

I'm thinking it's the RAM or the CPU. Are you getting any beep codes? I believe what is happening is your PS is distributing the power to your components but you aren't getting to the point in the boot sequence where it will search for all of your drives. Listen closely to the hard drive, it should spin up if this is true...
Back in A+ class we worked on P3 600~ MHz machines and when we had video card problems, the motherboards would not issue beep codes. If the hard drive isn't spinning up, then there's something wrong with the way the power is getting to the drives(and other components)