Another thing it could be is the injector itself, try another one. I use winject (look for it on google) and also AudiTT made a very nice injector (you can find that by searching the forums for his hack manager)
But really you should post more details when you post... ie: What injector you're using, any other hacks you're attempting to run (vac chaos often causes issues with injection), and if you are having problems injecting in general or if it's a specific dll (if this is the case it's probably the dll)...
One more thing ^^ "Plus the music how turn off!?" ^^ ... There is a topic on the main MW2 forum about how to do just that (you should read before posting people have a tendency to get a little irritated when you ask about something that's already here.)
Anyway just post here again if you still need help