Hi iamhives,
To make everything easier without complications, I would backup anything you do not want to lose on the older main computer, then do a clean install with
Ultimate on it.
When you install
Business on the new computer, you will have to do a
phone activation. Microsoft still thinks that it is installed on the older main computer until you do. This will show you how to do a phone activation.
Activate Vista by Phone
Shawn