I have two upgrade Vista disks. One is from Dell and is tied to the system, but the other one came with MCE05, and I do not want to change that one, it goes on a DVR. I do want to put it on my DX-10 gaming rig, probably dual boot. I have a new XP Pro to use on that system so can I upgrade XP Pro with the Home Premium upgrade?
Those upgrade disk will only do that, upgrade an existing XP image to run Vista. To do the dual-boot thing, you will need to update one of your systems and then install a copy of XP. One of them has to be a full install version disk that you can boot from. I don't know what Vista upgrade will do to a dual-boot XP system (both booting into XP).