Hi,
Did you get to the bottom of this?
I am having exact same problem, need Windows 8 maybe? Does it work?
I have no experience at all with Linux and there are no easy step by step guides to follow

If you are using 6 of any 200 series cards you have to use linux. The beta drivers you have to use for R9 cards don't support more than 4, even in windows 8. It is a driver limitation, not hardware, as 6 work perfectly fine in linux.
R9 cards won't mine on anything but the 13.11 beta drivers, it's not possible to use modified 79xx series drivers to get 6 working in windows (yet, give it time...)
I have tried 5 in one mobo with Windows 8 and 13.12 drivers.
I can confirm that works OK.
Windows 7 only detects 4 cards, Windows 8 detects all 5 OK and mines OK too.