I booted up my MacBook Air (running Mac OS X Lion) and the desktop doesn't have a menubar. I used option+right-click to relaunch Finder and there isn't an option to relaunch it. When I launch an application the menubar shows up. When I cmd+q to quit the application the application's window closes but the menubar then defaults to the last currently open application. Even if it's on a different virtual desktop.
When I reboot the computer I notice that the keyboard is no longer backlit by default. The keyboard only becomes backlit after I correctly enter my password. I don't know if this is related to the problem stated in the first paragraph. It may or may not be relevant. I don't know.
Any thoughts or ideas? I've never seen a desktop in Mac OS X that didn't have a menubar.
To recap: No menubar, no date, time, Spotlight icon etc. when all applications are closed. They show up when I launch an application. Option to relaunch Finder is gone.