Recently I rebuilt my pc and after reinstalling everything I was having problems with my mic, when I tested it in BF2142 I would get a lot of feedback and a repeating loop, despite everything working ok when tested in windows. After searching a few forums it seemed to be a problem with my motherboards onboard sound but none of the fixes worked. I have now managed to get it working so thought I would share it here for anyone that may be having the same problems.

I am using an Asus P5K/EPU motherboard with on board 8 channel Realtec HD audio, using the front audio sockets (for mic headset) I get the feedback, I also experience it using the rear sockets.
Your motherboard may be slightly different but if it features the same audio chipset this may work.

Go to control panel and open the Realtec audio software (looks like an orange speaker).
Go to the mixer tab and you should see a host of volume controls, with playback along the top and record along the bottom. Using the recording section click on advanced ( a little button below the main recoding volume knob) and you should see an option for stereo recording, turn this off.

Launch BF2142 and run the mic test, it should now work.

Note: for some reason this fix will still not register any mic when using the voip setup from within /programs/EA/BF2142 mic setup program.

Will edit this later with pics.

Bite my shiny metal Tie Fighter!