Gmod , Hlf2 , Css not starting up.

Alright , Recently I just rebooted my whole computer. Took out everything that was in the computer from steam to files to other stuff.
Now I installed gmod , hlf2 , and css. Now they don’t work When I try to play on it , It show’s gmod in a windowed mode which I didn’t put it in and it shows the valve logo & such. But never load’s to the loading screen