Catrin, thanks so much. I think it's my Thunderbird emails. I have lots of them, with lots of attachments. I don't need the attachments because I save them to our central server as I receive them. But the emails--I need to save alot of them for future use (in case of a lawsuit or something). I'll have to figure out a way to save them on our server without having to open each one and save as PDF.

I do defrag and disk cleanup regularly, but I'm sure there's more that I could do (like proper email management!)

We are a tiny business of 3 people in two states, and so we don't have an IT department. So again, I thank you very much. I will let you know if this solves the problem, at least temporarily. I'll still pursue the partition issue.