i have a G4 powerbook and logic 7 express. if i programm drums or strings (anything on software instruments) there is no sound i hear over my head phones. Did i sent up something wrong??
If i import a sound file in the audio section everything work fine. can you help me whee the problem is??

check your sysytem preferences

I'm having the same problem. I can hear recorded audio, but none of the generated instruments.

?????

Make sure you are using an audio instrument channel, also make sure you assign an output in the channel strip.