Problem with left 4dead 2

[gouthi]

hi,
i am goutham,i bought a game ''left 4 dead 2''i installed it but its not comming.i tried in sp3 but it did'nt come, is there any problem with os or the game.give me some suggestion.

 

[MCFCBlue]

Have you installed Steam? you need a steam account to run it.