You could have a number of things going on, but it's hard to say without knowing more about your system, your microphone, etc.
It might be worth contacting tech support and seeing if they can walk you through some troubleshooting.
Otherwise, it might be worth doing a repair/install on Vista and doing an uninstall/reinstall of Premiere Elements.
I don't know what you mean by " I have repaired PE7 in Add/ Remove programs".
Since you say that the issue is not present in a new project, then let us explore the damaged project angle.
Please check out the following AdobeTech Note on damaged projects in Premiere Elements 7 and see if anything in it helps resolve your situation in the problem project.
Let us start here and see where that leads us.
Thank you for responding. I went to Control Panel add/remove programs and had it repair my installation of PE7. It copied something from my original disk, but nothing changed. I sent a message to Adobe Support, but their system is down until Wednesday. I went through the troubleshooting damaged projects information, but I didn't find any applicable information. Since I have to have this project completed by Friday, I will narrate in Audition and import into PE7. Thank you for your help.