Screen flickers black for a few seconds

Hi!

Before I ask my IT department about this, I am wondering if anyone else has this issue? During a Zoom webinar, the screen will go black for a few seconds sometimes repeatedly. Sometimes someone is sharing a screen, but not always. I am using HD 720p. It could be so many things: a video card, a driver, or...is HD too much for my computer (I don't have the specs at hand, they are at work) - is this a possibility - does HD video demand a lot of processor or something?

Thanks for any insights you can give!