A Big Mystery To Me

Okay, having some problems with my system at home. I'm going to run
down a list of problems, things I've tried, and the results. I'm
stumped here, so I'd like whatever feedback is out there...

I've got a P4 2.4GHz processor with 512MB PC2700, GeForce 4 Ti4200,
Soundblaster Audigy2, 300w power supply, c:\ drive is a 60 GB Maxtor,
and d:\ drive is a 120GB Western Digital.

- Got home one day and the monitor was black. I rebooted the system
and got into Windows, however, my D:\ drive didn't show up.
- Tried rebooting again only to not be able to boot into Windows at all.
It would get to the Windows XP Loading screen, then go blank, wait a
few moments, and restart.
- Booting into save mode froze and died on me when it got to agp440.sys
(I think it is)
- I hastily installed Linux on a free partition on my c:\ drive, and was
fortunately able to recover many of the files on my D:\ drive and burn
them to DVD. Not the slightest problem accessing the drive or the data.
- I tried physically disconnecting the D:\ drive, and the system booted.
- I went into the Windows XP recovery console and ran chkdsk on the D:\
drive. It said it found one or more errors on the drive.
- The system booted up fine into Windows after this for all of one day;
I ran a chkdsk from Windows and found that the D:\ drive reported 4KB in
bad sectors.
- The next day it went back to going blank after the XP loading screen.
- I tried the recovery console again, chkdsk found errors on D:\, but
this time the system still didn't boot into Windows.
- I ran chkdsk on the C:\ drive and it said it found one or more errors.
- I tried using the XP disk to recovery my Windows XP installation. At
one point during the process, it reported that a dll couldn't be loaded.
After restarting the system and re-attempting this process, everything
installed properly. However, upon trying to boot into Windows I got a
very rare BSOD with the error message of "INTERNAL_POWER_ERROR".
- It did this every time I tried to boot the system. Finally, I gave up
and formatted the C:\ drive and reinstalled Windows. It booted into the
system fine, and everything seems to work well.
- I ran a chkdsk from Windows to happily find that there were no bad
sectors on the C:\ drive.
- I have yet to plug the D:\ drive back in. I'm kind of afraid to.

I haven't added any new hardware or any significant software on the
system in quite some time, and it appeared to have been running fine
under its previous configuration. I haven't a clue what started this
frustrating chain of events. I'm open for any input and/or speculation.

Kenneth