Hi
If you are not using the latest version (8.32) then hanging at 99.5% during export may be due to the fact that you have a reversed clip somewhere in the timeline. Check this out.
Save the project and then try again after clearing the cache
You could download the latest version and see how that performs.
https://www.nchsoftware.com/videopad/versions.html
Obviously save your original setup.exe file and your license code somewhere safe.
Nat