Currently Being ModeratedJan 6, 2013 12:13 AM (in response to jbdb008e)
On Mac Pro Aluminum Keyboard my Control & Option key on left side of Keyboard stopped working.
Because I'd set Windows login to require Control+Alt+Delete prior to password entry, this led me to reinstalling Windows because I was locked out.
After doing so, I realised that I could have been using the Command, Option, Control keys on the other side of the Space bar.
Don't be as dumb as me: if you have 2 of them, try the other Option/Alt key