Random box appears then immediately disappears throughout the day, been happening for weeks.

So I have a PC with windows ten, and for the last few weeks this has been happening. A random window keeps appearing for a fraction of a second, too short to see what it is or for it to appear on my task bar, then disappearing. It's like a program is running and trying to hide itself. Idk how to google this issue, since its so specific, but i assume its a virus?