Channels "3" & "4" are indeed your RAID IDE channels on the mobo REDBULL.
As regards the frersh install of Win XP the choice is yours really, if you decide to leave it as it is then you need to remove any of your existing mobo/O/B sound etc drivers/CDRom drives (if you are changing any of them) from Windows in safe mode before you fit your new Asus mobo and the various drives.
I myself would start over again but then I enjoy pratting about just to make sure I've got as perfect a system set-up as is possible.

But what I am saying is you do not really have to if you don't want too.