MagicDragon:  XP should be able to identify any modem you have.  Sometimes the problem has to be solved with your ISP as I've had to call Comcast a few times for configuration help.

MagicDragon: IF you are going on to dial up you will need an internal modem (you should have one already on your machine as standard ) should be no reason to delete or format anything on your machine . when you get your dial up connection xp will most likely find everything required .