Steam....

[Xaero]

When i open steam and go to open any game e.g: cs, hl2, hl source or anything like that a dialog box comes up saying its about to open and then it dissapears and the game doesnt load, any suggestions, much appreciated.

PS: Problem started 2 days ago.

 

[Xaero]

i reinstalled and i brought hl2 from a shop containing these games. 100% legit. Reinstalling didn't work , any suggestions?