Have a look here...

http://www.microsoft.com/windows/win...layer/faq.aspx

and see if any of the suggestions help.

Don't try to manually delete any of it's folders or files. They're regarded as system files by Windows and won't allow themselves to be deleted. That's actually a good thing because if you did manage to get them deleted you'd be creating quite a few problems since there are a number of other files, programs and registry entries that would be negatively effected if WMP suddenly dissappeared.