You need to install your audio drivers for the device in the computer. Normally, you would use your install disk, or download sound drivers for whatever is installed in your system.
You have not described your system and configuration so we cannot be of much help.

 

Codecs aren't an audio driver issue.

In the meantime, you might also try VLC Media Player which avoids most of the codec dependency issues often found with Windows Media player

 

Im using windows media player 11 - on Windows XP Professional 2002 version.

VLC player wont work either. When i ask for more info on the codec needed it says:
You've encountered error message C00D10D1 while using Windows Media Player. The following information might help you troubleshoot the issue.
Codec is missing

Windows Media Player cannot play the file (or cannot play either the audio or video portion of the file) because the Comverse Infosys G723.1 (A100) codec is not installed on your computer.

 

Looks like that particular codec will require a bit of work to find! Start here

 

Agree; Codec is an encode/decode for audio/video data