What version of Windows are you running on the computer in question as well as the OS which was on the computer that used to have the modem in it before it was formated? Also, what's the manufacturer of the modem (should be listed on the card or on the CD that came with the modem)? Finally, you say that you installed it into the AMR slot of the computer... was it in the AMR slot on the other computer as well? I'm not certain, but it's possible that, considering the difference of machine, the AMR slots are not compatible.
Oh yeah, one thing you may also want to try is to pull the card out and reinsert it. It's quite possible that it's simply not inserted tightly enough.
AJ
