Well it's actually difficult to imagine what he meant! Control clicking on the finder icon no longer offers relaunch in Lion, you need to bring up the Force Quit dialog using option command escape or from the Apple menu.

More curious is the fact that the OP said that rebooting didn't clear the problem but relaunching the finder did. How can this be?

I'm inclined to think that the other suggestions about clearing prefs and caches make more sense.

An Option-Right Click (and probably Option-Control-Click) on Finder will offer Relaunch. I think this is probably what the OP actually meant.

"More curious is the fact that the OP said that rebooting didn't clear the problem but relaunching the finder did. How can this be?"

A good question, really. Restarting does relaunch the Finder, so the sentence is invalid.