Howdy, dEdEI know you don't want to purchase another modem, but take a look at
this webpage for the scoop on WinModems vs Linux. Even if you should return to Windows, you'd probably be ahead to get a good external modem in place, and if you should do that, you'll most likely have great success with it under Linux. I've found that the US Robotics and Zoom externals work very well with Linux. I'm currently using the Zoom 3049 ext that I found for about $70 at the local computer store.
Perhaps someone else here will have more input. Anyway, good luck whichever route you take...