I installed it on a separate drive with my main Win7 drive disconnected so no stupid boot loaders got installed. Because I didn't have a blank dual layer DVD I just put it all on a 16GB SD card and installed it off that. My motherboard gives me a list of all connected drives if I press F8 at startup so I can choose what to boot from.

http://hexus.net/tech/tech-explained/software/31765-how-install-windows-8-usb-drive/