it looks like i solved the problem myself
first i did try to find out if some of my hardware was damaged or broken. switched the rams, started pc with only 1 each, everything was fine, but the problem was still there.
then i downloaded 3 different anti malware/virus programs and let them take actions. it found several things, i guess this is normal because they want to sell their product, but it also fixed my problem
now it shows 16 gb of ram when i go in the control panel / system instead of 7,98.
i m not sure how this could happen. was there a harmful program that deactivates or blocks half my ram? what is the purpose of this?
i m happy that everything is fine now and the problem seems solved.
my pc suddenly freezes every day, so i did try to find the problem.
it seems like my memory is filling up way too fast, so i got a memory clearer. now i saw that i only have 7,98 gb of my 16 gb ram available.
when i remove 1 ram stick i will have 8 gb, when i use both ( 2x 2x4gb) i have 7,98 (less). that doesnt make any sense for me.
i m using windows 10. is there a way to solve my problem?