Just a thought, If you do not have any other Serial Port devices,
this could be a result of on-board Com ports being enabled. To
check enter BIOS (Del, F2,...) navigate to Integrated Peripherals
if Com1 and Com2 are enabled - toggle their settings to Disabled.
Once back in Windows XP, Open Device Manager, Click View
tic "Show Hidden Devices". Then expand the Ports category, if
Com1 or Com2 appears "grayed out" delete them. You might
want to remove the modem while doing these operations. After
you clear all the enabled Com Ports re-install your modem. A PCI
modem has it's own dedicated Com Port on board and can cause
conflicts if the motherboard Com ports are enabled.