Screen problem - what to do?

For some time now my sister has had the following problem with her laptop:

When you start the laptop, it has to move the screen so that the box for logging in appears at all.

In addition, when she's using the laptop, the screen flickers and then she has to move the screen again so that you can see everything again.

What can that be? What can you do about it?

Well, that sounds like a loose connection that the brackets on the screen have.

alternatively, it could be that the sensor that detects the closing of the laptop (folding the monitor down on the keyboard) incorrectly detects the screen position. Thus, the PC "thinks" it is closed and switches off the screen.
the wobbling of the computer "loosens" any loose contacts and occasionally ensures that contact is established again and the screen comes on.

I see. Is the problem expensive?

Or can you fix it yourself?

The repair costs should not be low. I also doubt that you can do this on your own, even to replace the LCD connections yourself, let alone find such an LCD connection for your model on the Internet.