Some keyboard keys do not work

I have a problem with the keyboard on my laptop.

The following keys do not work:

3,e,d,c
note: these keys are diagonally in a row,

I’m not sure if that means it is is problem with the keyboard itself , or the controller.

Any idea ?

I’ve managed to remove and refit the keyboard and he problem persists, so it isn’t just a loose connection.

I’ve seen this problem before. When keys seated diagonally in a row stop working, most likely it is the keyboard related problem.