Horizontal venetian blinds on screen (NOT CAMERA VIDEO TO OTHERS)

Hi!  My daughter owns a "Lenovo N22 Winbook."  While Zooming her college classes, horizontal white "Venetian blinds" appear across the screen,  If she restarts the computer, the lines disappear for a while and then reappear shortly after she rejoins the class.  Others can see her and hear her without issue and she can hear them.  (NOT A CAMERA ISSUE).  Sometimes the lines continue for a little while after the ZOOM session has ended.  My daughter is able to watch "Netflicks," etc., over the Internet without issue.  She called me...  Any suggestions?  Please help!