Modem Found but not in control panel

Hi,
I’ve a system that has me perplexed. I can install a modem (pci,isa, or ext.; mfr. doesn’t matter), shows up in device manager, but not in ‘modems’ in control panel. I’m assuming a registry error, but in comparing the ‘modems’ registry settingswith other systems, it seems fine. My client is annoyed since this is taking so long. Can someone help me out on this! Much appreciated!