Does exactly what it says on the tin. Some of the nonsense contained herein may be very loosely related to The Sisters of Mercy, but I wouldn't bet your PayPal account on it. In keeping with the internet's general theme nothing written here should be taken as Gospel: over three quarters of it is utter gibberish, and most of the forum's denizens haven't spoken to another human being face-to-face for decades. Don't worry your pretty little heads about it. Above all else, remember this: You don't have to stay forever. I will understand.
When I record a track of audio in, any other tracks that already exist will mix themselves onto the track I'm recording. It happens when I'm playing something in using the Line In ports.
It's a set up problem with my soundcard I think (Soundblaster Audigy 2 Platinum Pro) as opposed to the programs I'm using (has happened both with Acid 5 and Cubase SX). I haven't played with the settings as far as I know, I just installed the drivers the way I did originally when I first started using the card (and I didn't get this problem then).