Question:
What would happen if I purchased a 2nd-hand game from a shop which had already been installed by someone else onto their steam account?
Example: I go into a shop and purchase a hard copy of L4D2 which had been traded-in by someone else. I then try to install it to my steam account - if the previous owner had already installed it to their steam account, would I be able to install/play it on mine?
I'm guessing not?

What would happen if I purchased a 2nd-hand game from a shop which had already been installed by someone else onto their steam account?
Example: I go into a shop and purchase a hard copy of L4D2 which had been traded-in by someone else. I then try to install it to my steam account - if the previous owner had already installed it to their steam account, would I be able to install/play it on mine?
I'm guessing not?
