Borderlands 2 wont launch

[Larry the Llama]

So my computer started to get REALLY laggy so I reformatted it and I reinstalled windows 7 and I try to launch borderlands 2 but it just says "preparing to launch borderlands 2" the window closes and nothing happens. I try to run other games but the same thing happened. I know my computer is good enough to run borderlands 2 cause I played it on the same computer I reformatted it. Please help.

[DraLLoC]

Try downloading the Directx Web Installer, and getting a fresh copy of DirectX.
http://www.microsoft.com/en-us/download/details.aspx?id=35

[Larry the Llama]

It didn't work :(

[Juzt_Lernin]

Close steam completely, right click on the steam.exe and run as administator. That has helped me fix/run quite a few steam games. And also, go to my games and right click Borderlands 2, then properties and verify files. You may have a bugged download.