Screen keeps semi-shutting down, with or without magic keyboard.

Screen goes blank with little turning "star". Sometimes this is when I am in a game (most recent was in a sudoku) or on a social media site or in a document writing or editing... Nothing I've tried returns screen to "on". Sometimes there is a brief return to live screen and then off again. Just recently I've had a combination screen or today's date and time size large and then a sort of cartoon from somewhere and below that at least one notification. (That last stayed on long enough for me to cancel it out qnd bring up home screen and attempt to go back to work . . . a half dozen times?) Once in a while it produces a bright pink pop of a screen and then it is off and I can bring it back on in the usual way. Suggestions? Further questions? N.B. I am only 1/2 sure this is an Air3, might be a 4.