Personally I'm pretty tech savvy, I hate the whole OEM thing. When they sell you a computer they should give you a fresh ISO installation disk and a disk with drivers on it. I'd pay a little extra for that.
I've purchased a student copy of Windows 8.1, not particularly happy about it as I do prefer Windows 7 but I guess it wasn't anywhere near as expensive as I expected so that's okay.
Pretty frustrated by the entire thing but at least the chat customer service rep that I spoke to was very well spoken and knew her stuff, unlike the phone team.
In response to you telling me I didn't pay for the operating system, I did pay for it, I paid when I bought the computer, I own the license to that product. It's just a technical thing to prevent people from re installing their copy too much to extract more £££ from people who want to upgrade components.