Screen freezing and black screen while viewing other's screen share during webinar

During  a webinar, after updating to the latest version (5.7.7) our PC experienced unique anomalies that other participants did not.  While other panelists were sharing their screens (Powerpoints) our screen went dark.  Our PC also lost the ability to switch between views (swap between large shared screen and presenter, etc.).  It just froze.  And after the panelist finished sharing their screen nothing changed.  Our screen remained dark.  Eventually we lost all picture.

We left the meeting at one point and logged back in.  Fine for a while and then problem reoccurred.  Became an audio-only Zoom.  This is an older HP Pavilion laptop with an i5 processor.  We'll be replacing with a newer computer but I'd like to get to the bottom of this before we possibly replicate the problem.  Thank you for your thoughts.