I have currently discovered a bug in the Adobe Reader 9.3 Update released on 1/12/2010 where in a multi-monitor environment one of the monitors or sometimes multiple monitors come up as a Moblie Display.
I have seen this happen when the update is applied on a Windows 7 64bit box with Quad or Dual Monitor set-up. Using Dell p2210t Monitors and Nvidia Quado NVS Cards (all models) not sure if this is only happening on other OS's with the same set-up but that's what we've seen. I have since stopped running the upgrade or roll it back on affected machines.
I wonder if ADOBE knows of the issue and has an update for it.