Win2K not recognising COM port

My problem is that my COM ports do not get recognised under Windows 2000. However, if I boot 98 off the same PC and hardware, the same device (modem in this case) get’s recognised and is usable.

Under Win2K, COM1 and COM2 have a yellow ‘unusable’ mark against it. COM driver issue ? Hardware incompatibility issue ?

What is the best approach to problem diagnosis ? Look at BIOS ? I was told by the product support folks that it is not a software issue; as I have just only purchased Win2K, Service Pack 1 is shipped and installed with the product, as I understand it.

Best Wishes and Many Thanks
Jude