Trouble starting HL2:Ep2

[gamebushido]

Whenever I go to launch the game it gives me the "preparing to launch Half-life 2: Episode 2...", but then goes to a "The game is currently unavailable. Please try again at another time."

Any ideas on why, and/or how to fix it? I really don't want to have to re-install the game.

 

[Acepilotf14]

Try restarting steam. If that doesn't work, maybe the servers are just overloaded.
..Try again at another time..