vid files download , but get this message when media player tries to open them Windows Media Player cannot play the file. The Player might not support the file type or might not support the codec that was used to compress the file.

Get xtra codecs or another backup player. Try http://www.land.ee/d_nimo_codec.html OR http://www.free-codecs.com/ and for a backup player try VLC which has in-built codecs: http://www.videolan.org/vlc/ (choose nearest mirror site)