Thanks for the reply Tom !

Sorry I've been off line for a few days.

No, I'm not selling hardware ..etc I'm a student, working on the final project of my curriculum.

What I exactly need, is to have say, two copies of the hives stored in, say %path1%\copy\ & %path2%\copy\ ...etc. when the system boots it sets %pathX% accordingly to the NIC's mac address...if mac==mac1 set path to %path1%\copy\ & load the hives/registry from there...etc.

The rest of the system (the whole system, not XP) is a bit more complex than this.

Any idea on how to do it ? (without old school reversing the ntldr, which might be hard)

Thanks !
cnc2.