external modem? internal modem?
hardware modem? software / win modem?
windows operating system?
if it is an internal modem, remove it from the computer case.
reboot the computer, then shutdown the computer, put it back in the computer case, and reboot the computer. i would think that windows would then find it.
if it is an external modem, just disconnect it from the com port, reboot, shutdown, reconnect, reboot, and i would think that windows would then find it.
don't know what else to say.