Your copy of XP...is tied to a system that you either no longer have or which no longer exists.
What was the manufacturer and model of the old system?
If you want to "add" XP to multiple OSes...the best thing would be to install XP first, IMO.
The settings and drivers reflected on your old hard drive...are for a different system and problems should be expected.
Changing a Motherboard or Moving Hard Drive - http://www.michaelstevenstech.com/moving_xp.html
Intel® Application Accelerator - Moving a Hard Drive to a New Motherboard - http://www.intel.com/support/chipsets/iaa/sb/cs-009290.htm