ZITAT
Handy Tip: Run Media Center in Widescreen (16:9) Mode
Do you want to test your extensibility application for widescreen compatibility without a widescreen monitor?
If yes, then...
Click Start --> Run.
Type 'C:\windows\eHome\ehshell.exe /widescreen'.
Click the OK button.
Using the mouse, click the 'Restore Down' button to run Media Center in a window rather than full screen.
Voila, a 16:9 implementation of Media Center.
Do you want to test your extensibility application for widescreen compatibility without a widescreen monitor?
If yes, then...
Click Start --> Run.
Type 'C:\windows\eHome\ehshell.exe /widescreen'.
Click the OK button.
Using the mouse, click the 'Restore Down' button to run Media Center in a window rather than full screen.
Voila, a 16:9 implementation of Media Center.
LINK !