I did manage to pick out this: "reinstalling windows again and letting it download the drivers itself".
Microsoft has improved Windows to get drivers but is far from perfect. That is, after Windows is installed you MUST install drivers and apps to complete the setup or you may have troubles like you described.
And here's where Apple wins every time for me. No two PCs are alike (rarely) so only you or your PC maker will have the instructions on what drivers and apps you need to install to finish the install.
TL;DR. Your installation is not finished.
So im asking here because i've tried everything i was told and could think of. a couple of weeks ago i found some old RAMs and i thought maybe I could use them in my computer. I plugged everything out and opened it up. All my RAM slots were taken so i took one of them out so i could check if the RAMs i found are even compatible and put it back in. I turned my computer back on and first thing i noticed that the startup logo and the windows logo were a bit "stretched out" or not as good in quality as they were i guess. Anyways, it got to the windows logo and after that the screen turned blacked, the monitor switched between the VGA and DVI options and said "No signal" and turned off. After three times i restarted it, it took me to the windows repair options and i tried repairing windows, it didn't work. I tried system restore and that also didnt work. I was able to boot it into safe mode and i once again tried the system restore and, again, it didn't work. So i tried reinstalling windows and it booted normally. Then i installed the graphic card driver (the graphic card is Nvidia GTX960) and when it installed it the image disappeared again and i was able to get past the windows startup logo only if i booted it in safe mode. So i thought that there was a problem with the graphic card itself and i took it to the shop where i bought the computer. They had everything (graphic card, hard drive, RAM...) checked out and tested and everything was normal. They told me that maybe i got the wrong drivers and that i should try reinstalling windows again and letting it download the drivers itself, which i did. Again, the screen went black the second it was installed. The monitor is connected via a DVI cable so i tried connecting the computer to my TV via HDMI cable (since my monitor doesn't have HDMI input) and it all booted normally. I tried connecting the monitor with DVI to my old computer and there was no image. I thought it was the cable and since it was still under warranty i took it to the shop where i bought it, they tested it and it worked. Next i thought it was the DVI input on the monitor and i took it to the shop too and they connected it to their computer and it all worked. They suggested that i try installing an older version of the driver and that also didnt work. I tried disabling startup programs and booting it in low resolution video and it didn't work. Only thing i can think of now is that, when they tested the graphic card, they connected it with a HDMI cable and that there is a physical problem with the DVI slot on the graphic card itself (because of the stretched out BIOS and startup screen). Other than that im out of ideas.
(btw english is my second language so i apologize for any mistakes)