I am running my iMac on Yosemite and am trying to partition it to use windows. I have an ISO image of Windows 8.1 on a USB. I used bootcamp on my laptop to create in install disk using this USB. However, it seems that my iMac doesn't support using ISOs to install Windows (it is a few years old) so I am unsure how to partition it and download windows? When I try to use bootcamp, it begins the first steps of downloading the latest support software and installing windows however when they are complete an error message comes up saying "The installer disk could no be found. Insert your Windows installer disc and wait a few seconds for the disc to be recognized.". Thank you for any help, I am at my wits end with this!