I keep getting the message "error downloading codec" when Im trying to view them through Windows Media Player 10...<d/l shows etc>
What type of file are you trying to open (i.e., .avi)? Need more information to be able to help you more, sorry.
More likely than not, you will need to download the DivX codec. Go to www.divx.com and get the free version. If that doesn't help, let us know.