Get on the IRC, some people randomly post keys.
That's how I got Jc2.
However if the guy has the game retail (that's how you actually get keys usually...) and also has the receipt, he can take your account if he claims hijacked account to Steam Support, or even/at least remove the game from your accoutn claiming he bought it and tried to activate it, and it didn't work.
Also, I am crashing every 2 minutes :V.
I PRETTY OH SO PRETTY.