I believe it is the processor. I looked at it and it looks as it was overheated because of the material that was used in place of thermal paste.

Symtoms:
As soon as the power switch on the PS is turned on the system boots without pushing the button on the front of the case.
The system starts to boot then stops with a long beep every 5 seconds.
When it does get past all of this it never completely loads the destop. Hangs at the wallpaper stage. Scandisk hangs if it runs.

What I've done:
Swapped PSU's
Swapped memory sockets and sticks
Unplugged all cables to all drives
Removed all cards except AGP
Reset the Bios by jumper

The system was butched by some kid by swapping cards around and loading a bunch of games. Device Manager was a mess in Safe Mode (when I could get to it) with all the stuff that was in there.

I have run into something like this before where all this weird stuff starts happening, though never a problem booting to the destop.
I have cleaned and reapplied paste to the HSF.

Before I run out and get another processor is ther anything else I could do? I haven't checked for virus's since I haven't gotten that far other than safe mode, but with a long beep even before the video card fires, I doubt it is a virus.

This is a KT133 MB with a Athlon 850 running ME (which I will change to 2k when this is settled).

Take a look here http://www.pcguide.com/ts/x/sys/beep/

That beep is trying to tell you something.

Jim

2 things RAM or VIDEO.
I had a bad rams stick, but I've seen bad ram sockets. If it happens again try to bend the ram a little to one or the other side, and hold bent as still as possible when starting up the computer.
Try to replace the graphic card, or use a pci one. You can try the bending trick but it is less likely here cos agp is only 66MHz.

As I stated I checked the memory by moving the one stick to another socket and I tried another stick also.
I didn't try another video card yet.

The first thing that I found wrong is bothering me the most. As soon as I applied power to the PSU the system started without pushing the power button on the front of the case. If I clear the bios it doesn't start untill I push that button as it should.
Again, I think that points to the processor.

It was the processor. I swapped it out (which I didn't want to do) with one from my other box and all is fine.
The thermal material that was used (not the usual paste) wasn't applied properly or was the wrong stuff and slowly overheated the chip.