Can't spot a problem. Check the PM link for the proof.
Wait for the violet caching line to complete under the preview window. That took less than a minute, as did HD export.
You don't mention the PC's specs. With the exception of simple projects, gaming-class hardware is often recommended. That goes for any NLE, not just Videopad. Be sure to use the 64-bit release; it better handles large, complex projects
Something else to try...
Use this free utility to uninstall Videopad. When it prompts for registry entries, select and delete them all. Reboot the PC. Then install the 64-bit VP release.
Of course, Save Project File AS routinely, giving it a unique # or name, so as not to overwrite prior saves. Using Save Project Files (no AS) will overwrite. From the HOME tab, the AS choice is available by clicking the caret to the right of the Save Project button on the toolbar. That way you're protected, and shouldn't lose anything.