how do i install an xp disc i bought but regestry code is missing can i use my regestery from my other pc
It isn't the disk that is valuable it is the product key. As a valid product key on a COA sticker didn't come with the disk you bought it is just an expensive coaster.
You can not use the product key from the other computer. The product key from the other computer is probably OEM and that key dies with the first computer it is activated on plus it can only be installed on one computer at a time
just like all retail or OEM licenses for Windows.