MacBook screen comes on but stays blank or has 6 Vertical purple Lines

MacBook turn on, screen slightly lights up so I can tell it has turned on but stays blank, occasionally screen shows 6 vertical lines. 5 purple 1 black in the middle. Also occasionally those purple lines turn green. Touchbar is on.

Connected to external monitor. No picture.

Also when computer is on fens don’t come on!

any idea what could be the cause of the issue?

no physical damage.

Thank you