Yeah. “Screen flicker”.
Sorry for my jokes…we can get serious now…
This sounds like it might be a video card problem, possibly having something to do with a video function known as “overlaying”.
What are your system specs - and especially your video card?
Also, what caused your previous installation of hexagon to become corrupted; i.e: what were the symptoms of your corruption?
Do you experience video problems in any other applications? Can you play movies on your system with no problems AFTER you reinstalled hexagon?