Here is another thought that does not contradict anything are restated.
Microsoft does allow the use of trial versions of its operating systems. At the present time, you should be able to find both trial versions of Windows 7 and Windows 8. On the Microsoft download site.
These versions will run without a product key for specified time. Usually 30 days, sometimes more. This is the easy and effective way to find out if a new hardware, buildings will work with Windows 7 or Windows 8. This program satisfies the needs of both the home experimenter and the Microsoft profit generation.
Simply said, if it is of benefit to you then pay for it. If it does not benefit you, you haven't lost anything because it was a free trial.
That is the best I can say