cubase 6 has no output

hey guys, i’m new to recording in general and have been starting to get into cubase 6. i’m loving it so far but today all of a sudden i get no sound when i push play. i haven’t changed any settings or anything but i did just instal superior drummer 2.0 if that could have any effect on it. i’m a total newb so any help would be greatly appretiated.

MacBook Pro Lion 10.7.3 GHz Inter Core i7 4 GB 1333 MHz DDR3 - ZOOM R24 - Cubase 6 - EZDrummer - Fender Guitars/Basses

What tracks are you running? Audio, MIDI, Instrument… What is indicated as the output in the Inspector?

Are you able to post a screencapture of your VST connections page, and your Project page?

I would suspect that your VST connections is reset in a way. Are you using Control Room or are you going just through the stereo out?
In any case check that your stereo out or Control Room out outputs are actually assigned to physical outputs of your audio interface.

And yes, a screenshot would help.