If it's at the system level, Mozilla mail will be stricken in the same way.
Other than that, you'd probably do well to review your proxy settings on the Connections tab of Internet Properties.
Yes, it's a 10MB download. That's about 10 minutes on 56k dialup. Hell, it's better than IE anyway.
On a P200MMX, everything's going to be slow, right? Might as well be *good*.