Intel advertises NUC5CPYH - (Celeron N3050) as being compatible with Windows 7. It is not. All my attempts to install Windows 7 Ultimate 64 bit on it failed. The installation would start, and when it would reach the first interactive screen (language selection) the keyboard and mouse would be dead, (not even NumLock would work on the keyboard,) even though both keyboard and mouse work fine on the BIOS screens of the NUC. On other occasions I managed to overcome this problem, (I don remember how,) and the installation would proceed to 99%, only to fail in the end with some error about not being able to update my computer's boot configuration or something.
Edit: be sure to read nucblog's comment below for a link to an article with instructions that might bring you more luck than I had.
In general, my overall experience of interacting with the BIOS of the NUC5CPYH was not pleasant at all. The spiffy looking BIOS screens were not welcome by me, as they were not structured in the perfect logical order that I would expect of them, and certain parts of them were clunky. Attempts to introduce an aesthetic upgrade which result in something technically more flawed than its ugly predecessor generally make a very bad impression, at least to me.
Perhaps the most annoying thing is that the initial screen with the prompts to press F2 to enter setup, F10 to enter the boot menu, etc. appears as if it requires not one, but two key-presses. It probably requires only one, but there is an initial period of time during which if you press a key, that key is ignored, and that's extremely annoying. Hey you, Intel BIOS programmers, I have a hint for you: if you are not ready to accept key-presses, do not display a prompt for them!