I have a 2012 ASUS ROG G75VW TS-71 that I bought used 2 years ago, the place that I bought it from, someone there completely wiped out the Windows 7 Home Premium x64 partition and installed Windows 8 in it's place. I still had my key from when I had a desktop computer for Windows 7 Ultimate x64, so that is what I'm running on this laptop.
I did try Windows 10, just like Windows 8/8.1 I didn't like it.
I have also had Linux running on this laptop as well.