I'm using Vista by the way
Check that the right Audio Driver and default output paths are selected under Edit/Audio Hardware Setup. I believe I've seen the transport controls greyed out when Audition can't find a valid path/driver for the audio--and you have to select separately in Multirack and Edit view.
Even if you haven't knowingly changed these settings, Vista and Win7 seem to be able to do some weird things.
Thanks a lot! I guess it just changed randomly. It did that with the recording device the other day, and I just had to keep checking it. I just didn't think it'd do that with the playback device.
I really appreciate the help