Crash when FAXing

Not every time, but about half of the time I try to send a FAX, my computer
locks up. I can do nothing except shut down and restart using the button on
my tower (I can't even bring up the Task Manager). As soon as I restart, the
FAX automatically starts sending, and is usually successful. On rare
occaisions, it locks up a second time, and I have to restart again. I am
using XP, and I have this problem whether FAXing from an application through
the print facility, or sending a fax by itself using the FAX facility in
Accessories. This problem is really annoying. Does anyone else have it?
Does anyone know how to fix it?