Oooo a barton 2800 😱
Should be a decent enough upgrade for you. You can overclock it a bit by raising the FSB. If you aren't going to overclock, then I would say that you should instead go with a slightly faster 3200 (2.2GHz), but I guess that also depends on how much you're getting the 2800+ for 😀. Your PC will certainly be more usable and feel faster, but understand that it's not really suitable for gaming (what most of us here really care about) and may be slower than an entry level PC you can get today.