Battlefield: Bad Company 2 has built-in PunkBuster which had been found compatibility issue with Easy Tune 6 utility. We suggest you to disable Easy Tune 6 before playing this game to prevent system crash.
Go to "Volume Control > Options > Properties > Adjust volume for", and click the Recording Item first. then please select Microphone in the "Show the following Volume Controls", and press OK Button to return to Volume Control window.
Check the "select" box under Microphone and adjust the Volume to minimum.