This has happened to me a few time now. While I've got MC 10 running (10.0.107) playing music, if I'm working in Internet Explorer 6, occasionally my monitor's display will double in width (meaning only half of the 1024x768 display will fit on the screen at one time. It really hasn't doubled, as all the buttons, etc. are still in their original locations, but the display shows them twice as wide and twice as far from their original location. If you click where it looks like the buttons are when it's doubled, nothing happens, but if you click where the buttons are supposed to be (not where they display), they still work. Today I noticed that down at the bottom of Internet Explorer it said Applet "Transision Sensor" started. I've no idea what this is, but my screen doesn't do this doubling thing when Media Center ISN'T running, so I've got to think that its something that's happening with MC10 interacting with IE (though I've no idea why it would do that, as it isn't a MC page I'm viewing). Closing MC doesn't fix the problem, but closing IE does, so it's definately some inter-relation going on that's causing the problem.
After a bit more investigagion, it seems that the next item on the playlist (I'd been plaing MP3's) was an mpg video. When that started playing is when the screen "doubled".