When you try to play a DVD in Microsoft Windows XP Media Center Edition or in Windows XP, you may receive the following error message:
"Media Center cannot play this DVD. The DVD may be in use by another application or it is copy-protected"
This problem may occur if you are trying to playback a DVD that has content protection encrypted to an HDTV over component video able in HDTV modes higher than 480p. To resolve this problem, lower your Media Center screen resolution to 480i or to 480p. This is by design due to Macrovision copy protection. If your HDTV has a DVI or HDMI input, you may choose to connect your PC using a DVI cable or a DVI to HDMI cable which supports higher HDTV modes when playing back DVD content.
This message may also appear if you have two monitors connected to your graphics card and set your dual monitor configuration to Clone Mode. Change your dual monitor to Extended Desktop/Dualview Mode.