First, to boot you need to have an OS on the drive so if the only drive with an OS is C you won't be able to boot them. 2nd, you can't copy and past an OS. There are programs like Acronis True Image that will let you copy the C to another drive. So you can either get something like Acronis or reinstall XP on another drive. If you do this, I'd take out all the drvies other than the one you're installing Windows on and then reconnect them after the install. If you install the drive that had Windows on it, I'd format it.