Win 2008 and XP on 2 drives


My Windows XP machine died and I want to take the drive out and put it into a server machine that is running Windows 2008, and then be able to boot either XP or 2008. I've got the new XP drive installed in the server machine and I can see it from 2008. What should I do next to get the dual boot working?
If the XP system came pre-installed on the dead machine, it will have an OEM EULA which ties it to the defunct hardware. It is not transferable to a different PC.
If it's a full retail copy, and you've got the CD, you can transfer it to another PC but it's very unlikely to boot unless the hardware of the two machines is virtually identical.
You will most likely need to "repair install" to pick up the necessary drivers, and if the XP CD precedes SP2, it will not have SATA support and even that won't work until you get drivers from your mobo manufacturer's website.