Broadband problem with XP

Something weird is happening with my internet connection. Yesterday, I noticed that I couldn't connect to the Internet from XP. At first I thought it must be a server problem, but then I had a hunch, and I tried connecting through Win 98. It worked. I went back to XP to figure out the problem. I had downloaded Audacity, an open source software, last time I worked on XP-- and then had immediately shut the computer down. I thought maybe this software was causing the problem. I uninstalled it, and the internet was running back up!

Today the same thing's happened-- I'm not able to connect to the Internet from XP while it's working absolutely fine from 98. Could I have been mistaken? Could it be it wasn't Audacity after all? Since I had retired immediately after downloading it that day, I don't know if the Internet stopped working right away.

Anyone any idea what might be wrong?

Thanks!