I am running an HP Pavilion Elite HPE 400y connected via HDMI through a Sony Receiver into a SamSung XL-2370 LED Monitor. On the HP I'm running Windows 7 Home Premium 64-bit. When I go to Control Panel / All Control Panel Items / Display and set the screen display size to Medium (125%), Adobe Reader 10.0.1 moves the top of the document being displayed upward to hide most of the menu bar. Also, the tools bar is usually unstable. I can't use any of the menu because mouse clicks in the narrow portion of the menu bar that is exposed are ignored. To shut down Adobe Reader I must start the Windows Task Manager with CTRL-ALT-DELETE and then knock it down because the X on the upper right of the menu bar is hidden. When I set the screen display size to Smaller (100%), which is the usual setting, everything works fine. I like using the larger image size (older eyes), but I can live with the normal size. Unfortunately, to change the Windows image size you must log off your session, so it's not something I like to do more often than necessary.
This appears to be a problem with Adobe Reader 10.0.1 not adjusting properly with the larger image size. God knows what it would do if I used the Larger (150%) setting. Maybe there aren't any old people at Adobe who need a larger image. Otherwise, I'm sure it would have been noticed by now.