play head wont move

Audition 1.5 on an HP pc

opened the working file, an mp3, destined to be a podcast, but play head wont move either by space bar or on screen button. Fast forward works. as well as end and home. Is this a reinstall?

or just a settings thing.

Thanks in advance!!!! (of course I'm down to the last hour of edit on a 12 hr project!!!!!)

HalB