"Can't show Add/Remove Program list"
plus
"windows 2000 Server evaluation with SP4, SQL 2000 with SP3"

Makes me wonder if some worm or parasite found the machine. Nothing in your post details what you are doing to keep the pests out. If you think an Antivirus works on worms, then you need to research more. Here's a note about 5 tools to find most pests.

Parasite removal programs.

http://reviews.cnet.com/5208-6132-0.html?forumID=32&threadID=1313&start=0 notes the five scanning tools and removal tools that are fairly safe. If one does encounter an issue, its always been damage done by the MALWARE. The most common issue being Layered Service Provider replacement which you can use LSPFIX (Hint: use http://www.google.com to find).

The thread has follow on discussions about new links if you don't want to use Google to find an item.

Bob

PS. All the tools are free.