For non Blu-Ray DVD's you need the DeCSS decrption library -- usually obtainable in Linux Distros as LIBDVDCSS.
An easy way to get this for Windows is to install a trial version of say WINDVD. Don't activate it. Now install VLC -- some versions of VLC won't have the DeCSS library in it so it will pick up the DeCSS library from WINDVD.
Play a DVD with VLC and whilst playing uninstall WINDVD -- it won't remove the DeCSS library while its being used in another application.
Now you should have FREE DVD playing. And tell all those smarmy DRM supporting Lawyers to "Go and Make a sexual Move with a Duck"
So long as the decryption library (not sure what the windows .dll file is) but once it's installed then Windows Media player will play commercial DVD's.
That's why installing something like WinDVD will work as it has the built in decryption library. When uninstalling so long as you are using VLC or Window Media player WinDVD won't remove the decryption file.
Mine was working, but all of the sudden it quit. I get the following message
"Windows Media Player cannot play DVD video. You might need to adjust your Windows display settings. Open display settings in Control Panel, and then try lowering your screen resolution and color quality settings."
I have dropped my screen resolution as low as it will go and I still get that message.