Windows Media Player - can't make it default player

I can only get audio and no video when I am viewing sites that have a Windows Media Player File. I have tried to select it as default in the "Set Program Access and Defaults" but it doesn't save the change! I have tried removing the WMP software, downloading the latest version (11), going back as far as possible (January 2007) and restoring the computer to that time, etc.

I have tried everything that I can think of, but I am stuck! Can anyone help? Thanks!

 

K-lite Codec pack might help, it's free too

http://www.afterdawn.com/software/video_software/codecs_and_filters/k-lite_codec_pack_full.cfm

 

Thanks for the suggestion, but my system is worse than that. Every version of the Codec they had downloaded but I either didn't have permission to run it or it would give me the message that the download was corrupted. Their is something in my system that will not give me full admin rights! This is the root of all of my system problems. Any ideas? All are appreciated.