Dock/Expose not working, Desktop stuck with gray background (Lion) I am running Mac OS X 10.7.5 and the Dock/Mission Control/Desktop functionality is totally broken.  My dock is not present after startup so I have to start all applications from Spotlight.  I can't even alt-tab between them as the process that controls that function is also down.  My desktop is working but the background is permanently stuck on Gray no matter what I change it to.

killall Dock reports that there are no matching processes that belong to me.  I have removed the plist and db files for Dock and Desktop (com.apple.{whatever}.plist) in the Preferences folder and rebooted multiple times (both Safe Mode and regular) and nothing will change.  Does anyone know what might be wrong? Looking for a solution short of a full reinstall.
I had a similar issue, and running killall -KILL Dock in terminal worked for me.