"已告訴過你，XP是會認機器的"--not always true

i have put my laptop installation into my desktop (not the other way around though)

it's complicated but can be done.
mostly the issues are re-installation of the drivers (desktop has CD drive so no issue).

After installation of drivers for the hardware on the destination machine (desktop in my case), I removed unused drivers for the source machine...

not too bad...