I know it's not the hard drive itself. I purchased an external case that connects to the computer with a USB connector. I popped my hard drive in the case and connected it to rogonandi's laptop and I can access all the files on my hard drive. I have run virus scans as well as integrity scans on my hard drive, and no problems were detected.
I also started the laptop with my hard drive reinstalled and let it sit at the f8 startup menu for an hour without a problem. It only has a problem somewhere during the startup of Windows 2000. So I'm guessing that there must be a corrupt or damaged file that is still readable, but no longer contains valid data.
The bummer is that I can't reinstall Windows 2000 or even install XP or Vista, because my laptop driver discs are in storage in Maine. I didn't think I'd need them right away. I haven't needed them in four years. Why would I pack them?
The next step is to contact the company that sold me the laptop (four years ago) and see if there is any chance that they can obtain, or have lying around, a drivers disc for me.
In the meantime, I will attach my hard drive to rogonandi's laptop whenever I need to and access any of my documents.