Baffling recording problem in Audition 3.0, please help!

Question

i have this totally silly problem with audition 3.0, which until today was working fine.
the problem is simple but infuriating. i open a session, load a music track into track 1 and attempt to record my voice on track 2.
audition records, on track 2, the output from track 1 as well!
this problem started after i installed two pieces of software on the computer: van basco's karaoke player and audacity.
i've uninstalled these two programmes, restarted the computer, uninstalled and reinstalled audition (twice!) but nothing seems to work.
does anybody have any ideas?
thanks in advance
a late news flash. i haven't actually cracked it, but i've found a way round it that works: i add a bus track and send the output of track 1 to that bus track. that way the track 1 content doesn't get recorded on to track 2. a bit heath robinson though!

Answer 1

since i've now, thanks to ryclark, totally cracked this problem i think i can help!
probably you need to alter not your sound card setting but your windows mixer settings (i assume you're using windows). you can do this easily from outside audition (even with audition not open).
open the windows volume master (double click on the little speaker icon), in its control bar click "options" then select "properties". click on "recording", click on ok, then in the volume control panel that opens select only the microphone (or whatever you're using for your mike input) and disactivate everything else.
you should now be able to record in audition only what comes in through the mike.
hope this helps.