My laptop did not come with any CD's when I bought it from the shop. I am getting a lot of error messages when trying to run Windows Live Messenger like "system32/MSACM32.dll is either not designed to sun on Windows or it contains an error"

I have tried reinstalling msn but the same problem still stands!
Also I cannot seem to play music from youtube or any other website but my Windows Media Player plays audio fine.
The error message for that is "system32/dxva2.dll is either not designed to run on Windows or it contains an error"
Somebody please help me

I have tried reinstalling msn but the same problem still stands!
Also I cannot seem to play music from youtube or any other website but my Windows Media Player plays audio fine.
Somebody please help me

My Computer
- OS
- windows 7 professional 32 bit