Is there anything else in a PCI slot? such as another modem, sound card, etc?

 

If they work, that would say the PCI bus is OK and the expansion slots are functioning properly.

 

If there is another modem (one that came with the PC), remove that modem as two modems may cause a conflict. 

 

A little more info, other than "it doesn't work" would help.

Well...thanks for the look, but I tried a different modem in the PC and all worked fine.  I guess the modem I had been using had gone bad????  Anyway, all is well.