my primier elements won't play any more. I can edit but can't hear what I did

It is not clear what you mean.  Is it that everything is working and you can't hear the audio track?  If so, check the Preferences section for Audio Hardware.  Double check the output setting is correct for your computer.  Then make sure you've not muted the audio track with the buttons on the left side.  Check your computer's volume setting too.