My PC infinitely restarts

While playing a PC game on my computer, it locked up and froze. I could ALT+Tab between the game, AIM, Maxthon, and WinAmp but nothing more than that. The mouse moved but would not click (no rollover actions). I grudingly held the power button on my PC down until it turned off, then restarted it.

The PC loaded, checked my devices at boot, and the Windows logo appeared as it loaded. Then, it restarted, and repeated the load, device check, Windows logo… repeat infinitely.

For the record, my PC has a P4 3.06GHz processor, 1024Mb PC2100 DDR RAM, a Radeon 9000 Graphics Card, and has an 80Gb primary HDD and a 120Gb secondary drive. I also have a third 120Gb HDD that I swap out with the secondary sometimes if I want to pull data I have on it.

I ran through all 3 Safe Mode choices, with similar results (infinite restart).

Unable to find my WinXP disc, I popped in my Partition Magic Pro floppy disks. Once PMP started, I noticed an asterisk next to my HDD name and ran a check on it. PMP told me the drive was improperly mounted, but for any fixes, it said to refer to their online guide (which I obviously could not do).

So I reluctantly grabbed my Windows XP Install Disc, hoping to get a Repair off of it, and inserted it. When it booted, it loaded all the usual stuff it loads that takes about 5 minutes, before the bottom finally says “Starting Windows…” At this point, I got a blue screen with, in the top left corner in white text, a message that said the following:

STOP: c0000221 Unknown Hard Error
\SystemRoot\System32
tdll.dll

My only idea is that my HDD had gone bad. So I opened the case and disconnected the power and cable to the two drives that were hooked up. I took the third that I rarely use and hooked that up exclusively as a primary master w/ no slave and restarted with the Windows disk. I figured if I installed Windows on this drive, I could load up my PC with the faulty HDD as a secondary and do whatever tests/fixed on it that were necessary. However, I oddly got the same exact error above.

At this point I figured perhaps something was wrong with the BIOS, for it to be infinitely restarting, and giving me the same error message despite different HDDs, so I removed the battery from the motherboard for a few minutes, replaced it, and restarted. Same results.

I’m out of ideas. All I know is I need the data on that original primary HDD. I do freelance design and have a job for a client on that disc, as well as a whole lot of other stuff. And it’s difficult enough to work on a project without a PC; it’s harder if you lose all the assets you’ve created thus far. I’m hesitant to take it to a PC place (like Best Buy) because they tend to format, reinstall, and call it a successful fix.

Anyone have any suggestions?