After changing to the new pc i got my old hard drive so i don't have to reinstall all my steam games, everything works except cod4 and i never really has issues with the game. I've noticed that trying to start multiplayer always lead to a crash with the window "Iw3mp.exe has stopped working". i did try this fix -- > Go to Start -> Control Panel -> Hardware and Sound -> Sound -> Manage audio devices. Go to the "Recording" tab, and right click in the blank area in the middle. Select "Show Disabled Devices", and the device "Stereo Mix" show now show. Enable this device. Then again a thing called "Stereos Mix" doesn't come up. So that seem to failed, would anyone let me know how to fix this, cheers.