The Ultimate Computer Problem

Here's the problem (its long):

My friend wanted to play a game on my computer. He thought it was frozen, so he hit the reset button on the front. It restarted, but displayed a floppy drive error. Another restart. From then on, the computer went into a restart cycle when it booted up, but only when the floppy drive was plugged in. If we unplugged it, we got 8 short beeps (video error). The screen showed only the menu of options for the monitor.

We replaced the MOBO, the sound card, and added a second hard drive. Plugged everything in, booted up, still just the menu of options was displayed, but now, no beep codes. I took out the video card and used the MOBO video, same thing. I unplugged everything but the master HD, CPU, MOBO, and one stick of 256 MB memory, nothing happens. Now when it boots up, regardless of the floppy being plugged in, there's no reboot cycle, only the menu of options for the monitor is displayed, and the hard drive barely spins up before it hangs and just spins from then on, with no sounds coming from it like its doing anything.

We thought it to be a power issue, tried different power supplies, same problem, tried different video cards, same problem. The only thing I haven't replaced or unplugged is the CPU, so we think it may be that.

SPECS:
MSI ATX Socket A MOBO
1.3GHz Athlon CPU
512 MB SDRAM
GeForce 4 MX 440 Video
Sound Blaster Audigy 2 Sound card
20 GB Western Digital Caviar HD, 80 GB WD Caviar HD.

Anybody got any suggestions?

And how does your problem relate to 'Web Hosting Requests'???

I suggest that you be careful and post in the right forum, but I also suggest that you check the CPU for some sort of failure since that seems to be the only unique component (except, possibly, the memory) that has followed along through each test.