I have this simple Sound Recording/editing program called Audacity. I'm sure someone round here knows it.
Since quite some time now I've been having problems recording:

When I record a Track it immediately gives feedback Sound Creating a terrible echo-effect. It's much like when using Audio-Conversations on MSN and having both the Microphone and Your Boxes-Volume turned up to the max. You know that sound.

Now when I record Music I record 1 track, then I play it again while I record another piece of Music over it, playing on the beat of the 1st recorded track. Now that isn't possible anymore since that maddening Echo-effect turned up.

Can anyone who has any knowledge of Audacity tell me how I might stop this feedback echo effect from happening while I'm recording a track?