Man!
I bought a copy of Windows 7 Home Premium (32-bit) from a guy on eBay, and what I got in the mail was nothing like I'd hoped I'd get. I'd hoped for a new, in-the-box copy. Instead, I got a disc that said something like "Intended for distribution with a refurbished PC" on it, and an obviously peeled-off product key stuck to the back of the sleeve.
Great.
In hindsight, it was probably foolish to expect more for $27.99. Would it even work?
Well, kind-of. I was able to install it in VMware and the key worked at installation time, but when I tried to Activate Windows, it failed with an error saying that Microsoft had blocked that key!
Wow.
So, maybe the guy bought a refurbished laptop which eventually died, and he resold the disc that came with it, along with the product key that he peeled off of the laptop???
Conceptually, that seems like the kind of thing that something one ought to be able to do. But, of course, logistically, if Windows 7 had already been activated on the laptop, then after it died, there's no good way for Microsoft to know that, or any process that I know of to deactivate a key, and it ends up being up to the new owner to sort it out.
Fortunately, I was able to do so, very easily.
MS has a new (well, new as of August 2017) online chat thing that you can use for customer support at https://support.microsoft.com/en-us/contactus/. I typed in my problem, it gave me a potential solution, which didn't work, and then asked me if it solved the problem. Clicking No gave me the option of chatting with a guy, and the guy was able to get everything going.
It did require a bit of legwork though. I had to take a photo of the product key and a screenshot of the eBay order and put them on the VM's desktop, basically as proof-of-purchase. Then, I had to go through some steps to let him take over the PC. He looked at the images, "convinced his supervisor" that I had legitimately purchased the product, generated a new key, activated Windows with that key, and left me a copy of the key on the desktop.
Excellent!
So, if you find yourself in a similar situation, you may not just be out $27.99. There is hope.