MMDevAPI.DLL crash

[TheGodfather]

I bought the game today and it crashes at start up, I have downloaded and replaced MMDevAPI.DLL with another MMDevAPI.DLL that I found on the internet (it was about 100kb bigger). The game worked but sound didn't and my audio drivers were broken after as well. So I replaced the file with the old one and the game doesn't work again. Any Ideas?

Problem signature:
Problem Event Name: APPCRASH
Application Name: arma.exe
Application Version: 1.18.0.5281
Application Timestamp: 4b1915cf
Fault Module Name: MMDevAPI.DLL
Fault Module Version: 6.1.7100.0
Fault Module Timestamp: 49eea5a7
Exception Code: c0000005
Exception Offset: 00018d65
OS Version: 6.1.7601.2.1.0.256.1
Locale ID: 1045
Additional Information 1: a7aa
Additional Information 2: a7aa91f17ea749d42a4de3b390fa5b3d
Additional Information 3: a7aa
Additional Information 4: a7aa91f17ea749d42a4de3b390fa5b3d