Video unworkable

A job came in for a soundtrack for a video. I had to use Cubase 5 because video is unworkable on Elements 10. I tried everything, ProRes, low res, different types, codecs, this and that, but it’s just unusable. It plays at 2 frames per second, i.e. choppy, laggy etc. I went back to Cubase 5 because it has … QuickTime, which was, obviously, discontinued.
16G ram, i7, Nvidia GT120, Windows10.

It sounds very odd indeed, can you share the video so I can take a look at it?
I’ll be happy to analyze it for you, and tell you why it’s giving you such a hard time in the correct video player.