I have an older iMac. I'm sure it has iMovie on it. I'm going to move the clip there and, if it works, do my editing on that. Or, I'll find a different PC-based software program. If something else works, then I will want to get a refund.
I sure do appreciate the time and attention you've given me, but as someone whom has been in the software world since the 80's, I find it hard to fathom that there isn't an explanation for this. I know my PC isn't new but it certainly isn't underpowered or slow. The ASUS laptop I tried, with the same results, has a current generation Core i7 CPU and, while it has integrated graphics, I think it is plenty sufficient to handle the relatively basic editing that I'm doing.
As it is, the very basic issue remains: I'm loading an HD MP4 video and VideoPad adds artifacts. Maybe my partner whom is relying on presenting somewhat professionally edited videos would be OK with the distortions, but I am very disappointed with the result.
Not disappointed with your efforts, though. You get my thumbs-up. If you can think of anything, please let me know at your earliest convenience.
Sincerely, Robert