Rizwanshfiq,
The problem here is not CODECs (though you probably needed to update them anyway). There are a number of bogus files, usually with popular titles, that attempt to get users to download a special player that will probably take over your computer.
To avoid this and other problems, such as mis-named files or poor copies, you should use the Bitzi link before downloading. More info here:
http://www.gnutellaforums.com/open-d...owse-chat.html Bitzi will save you many hours.