My laptop stopped working because I wanted to upgrade my RAM?

I installed 8GB of RAM in my notebook and wanted to expand to 16GB. My laptop can have up to 32GB of RAM and also has two slots to plug in. I have already plugged in the new 8GB module and it doesn't work with my old RAM either. If I plug in both of them, the monitor does not come on when starting, but both work individually. The problem is that the module is somehow turned around in the other slot so it always changes the side when I change the slots. Does this have anything to do with my monitor not working? What was already built in, Is crucial by micron from the manufacturer and the other from Micron technology both specified 3200 mt / s as the speed. They should actually be compatible with each other, I think it's just the slot that is kind of confusing. Or is it normal that the screen does not work if two RAM modules are not compatible with each other?

If it weren't for them, would it work if I bought the exact same module again and installed the two new ones?

Notebooks are usually "very unique", which corresponds to the compatibility of modules.

Usually you should take a look at the list of the motherboard manufacturer, in which the valid modules and combinations are often (not always) given.

If necessary, instruct the dealer to do this, as he then has to take care of it and can then be contacted in the event of problems.