I'm sorry but I can't do that at the moment. This is not going to make any sense, but I'll try to keep it short: There was a critical issue with my hard drives (older Samsung 1 TB disks). Firmware issue. I suspect that Windows 10 alters something in UEFI/BIOS or something, whatever it was it caused a slight panic situation since my hard drives started spinning up and down like every other second and this continued non-stop. I saw the health warning in the S.M.A.R.T readings in HD Tune on "Calibration Retry Count" was way off. So I had to get rid of Windows 10 quickly. The "spin up & down issue" was still there when I installed Windows 7, but I solved it by erasing my UEFI with a special tool called Flash Toolkit (FTK) and then reflashing it with an older UEFI backup, thus restoring everything back to safety (for the hard drives I mean).
Sorry, I'm waaaaay off-topic now. But I can't install Windows 10 with those hard drives until I get new ones.