I have been using ThinkPads for about 4 years and am presently using a T40. I seem to recall having this problem with an older machine a couple of years ago.
Here is what I suggest:
1. Download the current modem drivers from IBM. It is new, having been updated on December 1, 2003 (maybe because of other with this problem?).
http://www-306.ibm.com/pc/support/si...id=MIGR-4ZFS2T
2. Extract the file to your hard drive.
3. Note the location to which is was extracted. Probably C:\Drivers\Win\SWMDMLUC
4. Go into Device Manager through Control Panel:System:Hardware, right click on the modem and Uninstall it.
5. Go to the location where you saved the new drives, double-click on Setup.exe, and follow the instructions to load the drivers.
6. Reboot.
7. Pray that it works.
Good luck!
Welcome to the mystical world of Windows...