As far as i know you need to change your SID.
Maybe its wrong, maybe not! I never tried it.
To change your SID in Windows Vista, simply type into your Explorer
%WINDIR%\System32\Sysprep
then open sysprep.exe->select generalize->ok!
SID is same to XUID???
Windows dont have a XUID,only in OSX, as far as i know respectively it is called different.
The XUID consists of the UID of the system. And thats the SID.
XUID: "Removing xuid 110000170d5d0ef from the session because nobody is registered at that slot (slot 9)"