Hello Brink,
Thank you for the quick reply. And thank you for the welcome as well.
I followed your tutorial, and after checking everything the only setting that was different was the:
PCI Express -> Link State Power Management -> Off
For me it was "On". I made the change and so far (about a week) it seems that it works: the laptop did not wake on its own.
The "opening the display" just meant that I opened the screen/lid/display of my laptop up.
Which should not happen actually, since I set the action for "When I close the lid" as "Do nothing".
On all the other laptops I worked with this setting allowed me to also open the laptop without it turning on, but this is a bit off topic.
Thanks again and now that the world did not come to an end (May 21 was supposed to be the end of the world, later it was rescheduled to be October 21 and May 21 was to be the date of "Rapture") I wish you have a good day!
Gábor