Re: Windows 7 isn't easy to purchase anymore, if at all.
Read what I wrote.
Many system builders (like Dell) bought Windows 7 OEM licenses upfront (remember all those stories about MS claiming that Win 7 had a fast uptake rate because of counting these pre-purchases as shipped systems), so have a stock of licenses they can use to put on newly built machines. As I understand it, MS are no longer allowing OEM Win 7 licenses to be purchased, so they will run out at some point.
So you have one of those pre-bought licenses on your machine. The only reason you have to apologise is for not reading my post.