Go to windows or Microsoft download center and do a search for WMP. I'm using Win xp service pack 3 on an old laptop and downloaded WMP 11 when it didn't play DVD's someone told me it doesn't come with codecs or decoders.. I don't know but mine still doesn't work??? Anyway... when you find it download maybe Ver 10 or a lower ver. It will download then present you with instructions on how to install... "if" you follow the directions. My problem started when I tried updating Apples flashplayer... I think it may have destroyed my old codecs.. I'm not saying it did but......I don't know what the problem is.