If you are putting your harddrive with with an already installed XP system on it. As soon you turn it on it will blue screen on you.
But.
Before you shutdown your old system, if you use the "Reseal" tools you can make the OS as if you were a developer installing the system. Upon boot up of your new system if will start the "welcome" setup.
In your XP cd go here:
\SUPPORT\TOOLS\
or
Download this
http://www.microsoft.com/downloads/d...DisplayLang=en
Open the deploy.cab
Run sysprep.exe
make sure you have the "Shutdown" selected in the dropdown. Click the "reseal" button.
Dont do a darn thing. Let the computer shut down. This may take a few minutes..
Swap your part over.
Start the system and you'll see the computer will start to boot into the new user mode.
Have your cd key ready.
At the user section add a new user.. Not the same user name as you had before.. Enter the new user then log out.. Log into your old user name and you can now safely delete the "new" user you had to create