Is there anything else you can't access, like the Registry? I've seen viruses blocking the user from accessing things like that. It's a complete shot in the dark, though. Still, it couldn't hurt to run your antivirus software.
I'll have to keep that in mind. 98 and XP are the two operating systems I have the most experience with, so I just assumed 2000 would be similar to those. I guess I assumed wrong, haha.
Those specs should be perfectly adequate to run win2k, I run XP on my parents comp Which is a pentium 3 700Mhz with 256mb ram and also my my ex-gfs computer which uses a AMD K6 500mhz and 256 ram. Properly configured XP will run smooth on those specs.
I believe a clean install is the order of the day, if thats not an option then you could have some troubleshooting ahead