recording problems

Hello, I’m running Audacity 2.0.0. on Windows XP and having a little recording problem. Having successfully laid down a stereo backing track on track 1, I am now trying to record additional intruments via the Aux input on my computer tower to track 2. This happens successfully, but also records the backing track from track 1 onto track 2 as well as the new instrument sound. I find I can stop this from happening by muting track 1, but then cannot monitor the sound from that track.
Any ideas please ?

Did you follow along with those overdubbing/multitrack tutorials we wrote?

You hear the old track when you switch audacity to Preferences > Recording > Overdubbing. You should use the device tool bar to make sure you’re recording directly from the connection and not Stereo-Mix, Wave-Out or something like that. Those are “fake” connections designed to make it easy to record internet audio. They will mess you up when you’re trying to sing.