Being used on another computer?

When I played TF2, everything was fine, then I tried playing GMOD, and I got a message saying my Steam Account is in use. I tried playing TF2 again, and everything was normal.

Help?

someone probably just hacked your account adonly uses gmod on it wel mabye

What i understood of that, sounded wrong.
Try deleting Client registry.blob n your steam folder. it worked for me.

lolz at the guy above the guy above me. Steam will detect the steam account being in use not a specific game. People think they know.

Don’t take any chances.

Create a new password for your Steam account and see if you still have the problem.