Hello,
I get this error when I play a dvd....I have a gforce 4200 with 128meg,120 gig harddrive,winxp with all updates,1.0 amd cpu,512 meg memory...My dvd player will play in any other dvd software I use.Thanks Ernie

Windows Media Player cannot play DVD video. Open Display in Control Panel, and then lower your screen resolution and color quality settings. To view the DVD Troubleshooter, click More Information.

I have exactly the same problem!!! Any luck in a solution? i dont know why, given it plays avi, mpg, VCD files/discs ok. but just not DVD discs. Really frustrating.
Same thing happens in Real media player. so i think its not the programs. but i dont know where else to ask.

You could check this link although it applies to version 8
http://support.microsoft.com/kb/306318/

The problem is caused because you don't have a dvd decoder installed and wmp doesent come with one so i solde this problem by installing other dvd player like windvd or powerdvd ,anyway have a look atthis site to.
http://www.microsoft.com/windows/win...212_0x00000000

I found out the media player was corrupt. I installed my dvdplayer software and it worked fine.

Its not corrupt ,its comes with out and dvd codex ,when you install you dvd software it installed the dvd codex on you computer ,then wmp fides it and started using it .