This is a short guide on installing windows on a mac. My mac is an imac mid 2006 with a core 2 duo T8300 and 3 GB of ram. Results may change on machines.
There are two ways to install windows on a mac: The Safe Way, and The Break-It-To-Work way. Each are viable for their own uses and useful depending on what hardware you have and what you want to do. For example, if you have an A1181 Core Duo with an Intel T2500, the system is limited to 3 GB of Ram. OSX will not be the best choice because little sofware in the app store will support the hardware and OS the go with it (which will be 10.7.5 at max). Because of this you may want to run Windows or Linux. While I would prefer linux, that is a bit tricky and I honestly have not figured that bit out yet.
Now lets say you have a late 2007 - Mid 2008 macbook or macbook pro. These machines are old, but can run OSX 10.11 just fine although you can do the same method either way. Also taking into note what you want to do with the hardware will be something you will need to judge for yourself. While I may only need a Core Duo machine someone else will need a core 2, i5, PowerPC G4, etc. We also have to take into account that even if there are 2 exact models they will each have their quirks.
Now, the methods. Method One starts with actually having a windows 7 ISO, though in newer OSX versions you might be able to do newer (I only have 10.7.5 available to me). If you have a disc or bootable USB available open up boot camp and follow the instructions there. You will have to partition your hard disc as needed and if you only have one drive available take note into what you want to do where. When the guide is done you can reboot or choose to do later.
Before rebooting you should take the time to download rEFIt, an easier to use EFI boot manager. This allows for a lot more concise boot choices. You can choose to access windows, OSX, a bootable USB, any drive that has a boot partition, OpenFirmware, reboot, or shutdown. Take the time to install this because it will make a lot of things easier later on. Also note that if you install this it is technically installed on OSX. As soon as OSX is gone from your system, if you choose to remove it (more on that later), then rEFIt will be gone as well.
Now with rEFIt installed and bootcamp having diced up partitions for you, reboot and hold alt until rEFIt pops up and choose your windows cd/dvd. Install and you have a dual booting OSX and Windows machine.
Earlier I mentioned a rougher way to use the machine with just windows. Whether its apple fanboys that made things up or not, an Apple machine isn't exactly meant for things outside of OSX. Again, I found no base in this with my imac as windows 10 does just fine by itself.
When you get to installing windows, take the time to recognize the partitions. A small partition from OSX will be there from boot camp. This will be for choosing between OS' and can be a bit of a pain. You can delete that if you want as we already installed rEFIt as a simpler choice of boot utility. Alternatively, you can delete OSX altogether and actually have a decent windows machine. As I said earlier this isn't recommended by apple users though I cannot verify it and it all sound like jargon and bullshit to me.
Lastly, in case you were wondering, linux SHOULD install in a similar fashion. Either I don't have a linux option in bootcamp or I have to have partitions available beforehand and skip bootcamp altogether and boot through rEFIt. To my knowledge there is not a way to use GRUB, GRUB2, or sysLinux on a macintosh computer. Although I also have not attempted, but it should be noted that this is all loose information based on one imac. If there are quirks in your installation with your specific machine then it is either a difference between 10.7.5 (what is on my imac), or differences in the hardware. If any differences are in fact found then please note them in this thread.
Things to Note: When trying to just boot from a windows CD directly, please note that the keyboard and mouse lock out completely / USB just turns off. You get a screen for CD boot selection and it stays this way until you reboot and choose OSX, going one of the two ways I listed here.
When playing with AROS/Icaros I noticed that you can boot from the CD directly and use the partition manager in the OS to do as you like to the drive and even directly install. This will also force GRUB2 to install, which again, I am not 100% sure will even work.
Lastly Before installing OSX on a machine, if you are doing this all from scratch, and you intend to have multiple OS's it is a better use of time to set up partitions before hand. Triple booting will be a pain, but setting for windows or linux beforehand will save a lot of time as bootcamp took a half hour to part off 50 GB of space on my hard drive. Doing so beforehand and installing through rEFIt will take MUCH less time and using rEFIt as your bootloader will be easy and less of a hassle than messing around with GRUB and EFI mixins, in my opinon at least.
Hope this helps whomever on the forum!