Windows Media Player uses wrong CODEC

I have Cyberlink's Power DVD that was OEM on my machine for playing DVDs.  I also encode some custom MPEG-2 files for my work.  Theres are generic m2v files that just contain video and are burned onto CD-ROMs.  Windows Media Player 11 for XP is what I am using for my default video player so that is what plays back the m2v files.  I am having a strange issue with WMP.  While files are encoding, WMP uses a Cyberlink codec and plays my MPEG-2 files fine in their original resolution and widescreen format.  But when the encoding is done and I then try to play my MPEG-2 files it uses a PALM codec which plays back the files in a different resolution and wrong aspect ratio.  The really funny thing is what I am noticing in the status bar at the bottom of WMP.  When I am enocding, it says connecting to server and then downloading codec and plays fine.  When I am not encoding, WMP tries to log into some sort of server (perhaps Cyberlink's) and then says "error logging into server" and then pauses before opening the file.  Now I don't get a popup error, just a message in the status bar at the bottom of WMP in fact the message is so quick it's hard to read it.  To me it seems like it is trying to load a Codec, fails and then uses a different Codec.  My questions are, why the different Codecs at different times and is there anyway to tell WMP which Codec to use for each file type?  I was going to uninstall and reinstall WMP, but it tells me I can't because the uninstall files are missing.  Thanks for your help.