I have elementary OS (Freya) installed on my system, as the only OS, but now I will like to also install Windows 10 and make the system dual boot, I do not want to loose my files or settings on the elementary OS. I have searched online on how to do this, but most of the tutorials goes from Windows to elementary OS, what I want is the other way round.
Read this post here:
This post has good explained answers on how to solve your problem. These answers will also work for elementary as both uses GRUB.