When you install windows you have to format your hard drive thus losing everything on it, so you first have to copy the drive onto an external and connect the external after it is up and running again and transfer back the important programs/ information.
well I dont have an external hard drive...but I do have a 4gig usb adapter. I'll use that to only get important files and drop them inside. other than that, do i really need an external hard drive? I really dont need anything in my hard drive. and reforming is like reseting the partition right?