Windows media player 11

[#1]

Have been having some odd problems with windows media player recently in that it refuses to play some DVDs that it previously played.
sometimes it gets part way through then just locks with a message that microsoft is sorry but the program will have to close.
Using XP (fully up to date).
My question is, can I remove and then reinstall a fresh copy of windows media player ? also is it a easy thing to do ?
I did have a copy of Nero on my computer which I uninstalled and wonder if I have messed up some other files when uninstalling it.
The reason for uninstalling nero is that it threw up error messages when writing to cds/dvds so I now use CDBurner XP (a free program) thats easy to use.
Thanks for your help 

[#2]

I suspect that removing Nero might of also remvoed the codec for playing DVDs.
Have you tried downloading some codecs off the web and installing them?
The beset codec pack I've found so far is K-Lite. It seems to have codecs for reading almost every format available. I used to install all sorts of codec packs. Then found K-Lite and ever since I've only ever installed that. Never needed any other codecs (except for RealMedia and Quicktime).
K-Lite even has DVD codecs you'll be pleased to hear

[#3]

okrzynska,
I Will give K-Lite a try... Thanks for your response.