Cant hear other tracks while recording!

[wtm5000]

Hey guys,
I have been using audacity for a while and have completed several successful songs and this problem just started. I recorded a track (drums) which worked and I could listen to it and what not but then when I tried to record my guitar over that, it was recording guitar as usual, but I could not hear the drums in the background. Its really pissing me off! Did I mess with the settings or something?
Please Help.

[steve]

Its really p**ing me off! Did I mess with the settings or something?

Yes you probably did
Edit menu > Preferences > Audio I/O tab
select "play other tracks while recording new one"
(do NOT select "software playthrough")

[wtm5000]

now I see.
Thanks alot.