Premiere Elements 14 on Windows 7 (assumed 64 bit)...
What video card/graphics card does your computer use? If not Intel HD Graphics 2000 and newer, the please disable the preference for that card under
Edit Menu/Preferences/General, removing the check mark next to "Use Hardware Acceleration (works on Intel HD Graphics 2000 and newer)".
Do you have the latest version of QuickTime 7 installed on your computer along with Premiere Elements 14. QuickTIme should be version 7.7.8 for your computer operation system. Are you running the programs as administrator (from user account with administrative privileges)?
What are the properties of your source that you are importing into the project? Brand/model/settings for camera that recorded the video?
What is the project preset (See Edit Menu/Project Settings/General). What is the duration of your Timeline content?
What are you selecting as you Export & Share settings (please be specific)?
Let us start here, and then decide what next based on the details in your reply.