Command key stuck on apple magic keyboard

Hi, folks

I'm using my Apple Magic Keyboard with number pad with my MacBook Air. Suddenly, one of the Command keys is acting as if it's permanently depressed. (Yes, I know it's a tough world out there, but that's no excuse.) Result is that when I click a key that has a command-[key] combination associated with it, the Mac acts as if I'm issuing the command, not just typing the key. Example: Hitting the "b" key is treated like Command-b. In Word, e.g., this means that instead of typing a "b", Word toggles Bold style.

I've tried using compressed air with no effect. Thoughts?