i just did that a week ago... although, i pulled the combo card, as it wasn't working properly (just having modem and sound on the same card is SOOOO packard bell - ie wrong)... no issues.
if you are going to keep the combo card still in the computer, you may run into IO and IRQ conflicts... recommend pulling the combo card... if you still want modem usage, buy a modem to replace the combo card too... i have found decent winmodem cards for around 20 bucks(ok... winmodem and decent don't belong in the same sentence, but it is better than a combo card)... Shane
and now for the impressive abbreviations:
DOA, SOL, AWOL, PEBKAC, id10t, FUBAR