Just want to make sure this is all compatible...

[Joe C]

You can use a Skylake cpu with that board and use Windows 7. Although Windows 7's life time is now only 2 yrs, Grandma may or may not be able to easily make a radical switch, I guess it mostly depends on Grandma, but you know her better and what's involved in making an o.s. switch on her. (She may freak out because everything is changed and her M$ card games will be gone, and she may be asking you what's where for the next month... ect.)
There is also a method to prevent the Microsoft update that prevents you from using Windows 7 with a Kaby Lake cpu. Not a hack, it's just not getting the update that say's you can't update with a Kaby Lake cpu
Windows 10 will be much easier for you to install, but not so much for Grandma? Like I stated, you know what Grandma is capable of, Keep in mind that elderly have a more difficult time with changes

 

[PP Mguire]

I look at it this way if grandma went to Walmart and bought a new laptop or PC it would have 10. She'd have to switch eventually, why wait.

 

[Joe C]

Well I suppose that if Grandma wanted a new pc, she would have already done it, Grandson is going to fix up her old one. I stated Windows 10 is fine if G-Ma can handle the change. It's up to Mandingo

 

[PP Mguire]

I only said that because I have a feeling it's a "grandma don't buy a PC I can upgrade it better for much cheaper" kinda situations. Or "grandma your PC is so old" "Yea we've been meaning to get around to buyin a new one but we never do gosh darn" "Oh I can upgrade this one" "Well if you insist sweetie" kinda things.