Video resolution has somehow changed and I cannot get old setting back

I tried to play a DVD on my laptop today using Windows Media Center, which has always worked perfectly.
A message came up telling me that it was impossible to reproduce the DVD, and I could see immediately that the video (or screen) resolution had for some reason changed, as the screen size (for the error message) was smaller, centered in the middle of the screen, and with wide black borders on either side.

I have been trying to change the video resolution, but it keeps reverting to the incorrect one. This is just an issue with Windows Media Center, as the screen resolution is good for all other programs, and I did manage to get to watch the DVD using VLC media player.

Can someone suggest a fix for this? Many thanks.

Florio

I'd thought of that, but I'm not sure how long the video resolution has been changed (I hadn't watched a DVD for a while). In addition, all my restore points are very recent; I doubt that they would help.

Thanks for that, but it's Windows Media Center that I'm having trouble with, and not Windows Media Player. Do you know if there's a way of taking the Center back to its default settings?