Sorry.But I am not going to reinstall it, to see if the settings changes make any difference.The more installs/uninstalls that are made, means more corruption of files.This program was obviously not tested thoroughly, before release. I have Deskscapes 8 in my ther Windows 8.1. No problems. Works perfectly.
Installing and uninstalling software should not cause corruption of any files.
With regards to the issues you are having, it sounds like something on your system doesn't like the newer EVR video support. The most likely explanation is video driver issues.
Deskscapes 8 uses VMR-9 for video which is a different system which doesn't use as much hardware acceleration. As JanOscar shows in his screenshot, you can change DS10 into that mode if you wish (though MP4 files would still use EVR as VMR-9 doesn't support those)