Hello Andrew,
It works perfectly on every win7 computer I own, i3, i5, i7 with HD3000, HD4000, and NVidia cards....... but many have said on this forum that it doesn't show any video in win10.
Do you see the "corner drag handles" in both the preview and program windows when "drawcorners" is turned on?
Is your video file "good" for Vpt7? I don't know which formats it can read, but as it needs Quicktime installed it can show .mov files, and probably others that quicktime can cope with.
I know .mov files work, but I have not tried others.
You should post a screenshot of the "max window" that can be opened from the menu. The author will be able to help you then, if any help for your problem is currently available.
David.