Fax, Cannot hear dial tone anymore

I have been using the Fax regularly (Using Windows XP Home Edition SP2 Fax
console) without any problem.

I found one VERY useful feature when sending a fax, was that I could hear,
through the speakers, my dialing tone, the computer dial the number, The
ringing or engaged tone (or even a voice)on the other end of the line.

However, suddenly, this no longer works. I can still send and recieve faxes,
but I cannot hear anything through the speakers. (Apart from other non fax
related beeps etc.)All other sounds work, but not this audio signal from the
line.

Can you help me get this back please? Your help would Really be appreciated.

I have a Medion Computer (Pentium 4 with Windows XP Home SP2)

I have found (With the aid of Sandra SiSoft) that the Fax Card is the
Creatix Poly Media GmbH SAA7134HL Multimedia Capture Device.
Product ID: VEN_16BE,DEV_0003
Revision: A/2 (1)

Many thanks,

Sanjay