What version of Premiere Elements and on what computer operating system?
1. Do you actually have video plus audio on the Timeline that you can see and hear before export?
2. If so, what are you selecting under Publish+Share for your export?
3. Publish+Share/Computer/and then what followed by what choice in the Presets field?
Depending on your answers, there may be additional questions about source media and project settings.
Further details should help us to plan troubleshooting.