Laptop display shows strange stripes?

ma
1

From today on my laptop screen shows stripes which keep blinking:

Laptop display shows strange stripes

But that's only on my attached laptop screen on my 2nd monitor the problem isn't.

Laptop display shows strange stripes - 1

I tried to restart the laptop and long pressed the off button. What else can I do? That wasn't there yesterday.

Do

This one monitor seems to be defective. You won't be able to fix this at an acceptable price.