>I have a file association, mp3, which is defined to look for a specific EXE such as c:\program files\winamp\winamp.exe. So, when I click on a mp3 file extension, it tries to locate that program. However, the new winamp goes into c:\program files\winamp3\winampa.exe. As the old file doesn't exist, when I click on it, I obtain the dialog. However, that dialog doesn't allow me to reset that association. What's the best to fix that?

Did you try to start winamp from the windows start menu? It should restore file associatons.