Media Center Decoder Error

I see there is a large number of users with this problem.   I have several questions:  I tried to reinstall my operating system and message said my disc was older version that what was loaded on computer. (Not sure how or why this would be)    I was told that putting in this disc might bring up a screen for a selective install and that might have the media center "decoder"  on it.    After reading some of the posts I think this might not be the right disc.  (obviously I am not a computer geek!)   I have a Dell XPS 410.  I have the operating disc, two Roxio creator discs, Dell Dimension Resource CD and a Sonic CinePlayer Software CD that was included.   Could someone tell me if one of those discs will help me repair my computer tv.    If none of those cd's have the correct software on them can some one recommend a download that will do the job.  Thanks!!