copy/paste? Do you have any imaging software you can use to image the lappys HD?
The problem with running it from an external is that none of the hardware is the same, your best bet would be to image it to a similar lappy model and go wild from there.
If imaging and running it on another lappy isnt an option then just use the XP backup tool and back up everything you can and hope that everything goes alright with the laptop repair.