Steam game is suddenly not working

My games were working fine until today. i only have one game (off steam) but it crashes every time I try to launch it is Call Of Duty World at War but it was working fine 2 days ago i tried running as admin tried running in compatibly mode but it still crashes and there is no black screen it doesn't even remotely start up just instant crash message. I have even tried reinstalling the game as well as steam and no change here is the error

Problem signature:
Problem Event Name: APPCRASH
Application Name: CoDWaW.exe
Application Version: 1.7.0.0
Application Timestamp: 4aea1f46
Fault Module Name: StackHash_0a9e
Fault Module Version: 0.0.0.0
Fault Module Timestamp: 00000000
Exception Code: c0000005
Exception Offset: 00000002
OS Version: 6.1.7600.2.0.0.768.3
Locale ID: 1033
Additional Information 1: 0a9e
Additional Information 2: 0a9e372d3b4ad19135b953a78882e789
Additional Information 3: 0a9e
Additional Information 4: 0a9e372d3b4ad19135b953a78882e789

have you tried deleting (uninstalling) the game and redownloading it? Obviously you can do this for free as you have already paid for it but it might work?

well i have a backup that i made when it worked and it has been working for a while but just randomly started doing this