Even 98 has the drivers for that controller, OMG, anyway sorry.

Check that you didn't have the stick pulled out. What I mean by that is on the PS and PS2 the stick actually pulls towards you and reacts slower, not sure if its supposed to but all my controllers do. So it might have then been pushed in and seemed to become super sensitive. Else try re-calerbrating it like Archie says. Oh and for gods sakes do not reinstall the drivers/windows/or anything else there should be no need.

Final question is it USB or Gameport kind?