Sonic CinePlayer DVD Pack is a plugin that allows you to play DVDs on Windows Media Player. In order to fix the issue, launch Windows Media Player, and press the Alt key. From the Tools menu select Plugins, click Options and make sure that the Sonic CinePlayer DVD Pack is enabled. If you still have problems, navigate to Start > Control Panel > Uninstall a program, open Turn Windows features on or off window, expand the Media Features list, un-check the box next to Windows Media Player and click OK. Reboot your computer and enable the player again using Turn Windows features on or off option. If it doesn't help, check Software Informer database for alternative solutions.