Everyone should know that to install a Windows system on your MAC, you can do it through Boot Camp. In fact, boot Camp has a feature you might not know--make a Windows installation USB drive that starts your Mac. So if you have a MM to help her Mac to install Windows, you can be ready to install the USB flash drive in advance.
First, prepare the ISO image for Windows 7 or higher, and a minimum of 8GB USB flash drive.
Then go to the "apps" directory on your Mac, find "utilities", right-click on "Boot Camp Assistant" – Show Package Contents –contents, find Info.plist. Copy it to the desktop.
Then edit the info.plist on the desktop, you can use any plain text editor open for editing, find preusbbootsupportedmodels, modify it to usbbootsupportedmodels, in fact, the previous Pre is removed, Then save it.
Next, the Info.plist on the desktop will be overwritten back to the original location (in order to safely recommend that you back up the original location of the original Info.plist), you are done. The next time you run "Boot Camp Assistant," You'll find the option to create a USB-mounted drive. The next step is very simple, I will not elaborate.
Note: Air and RMBP and a variety of machines without optical drives can be done without modification.