Modem Dissapearance


my computer doesnt see my modem any more,
if i click on the phone icon on the menu bar then it only shows bluetooth,
if i open internet connect the modem doesn't appear there either and if i check modems in system profiler it says modem model: modem driver not found.
any ideas how i can resolve this.
i'm running osx 10.3.9 on a 12" g4 powerbook
regards martin