fax hanging up

Hi we had this problem once before and fixed it but can't
remember how, it may have been a complete hard drive
format. When a fax is sent it dials the number once then
hangs up the modem. I would be nice if it actually sent
the fax first. We are on win xp and our fax was working
till just recently, we have no idea what was changed that
caused it to stop.

Lady Kila