Nic.F wrote:
"and I didn't have a registry backup."

Forgive a newby's probably stupid question, but how do you backup the
registry?
I'm migrating from a p3v4x to p4c800 deluxe and this might, well
will, come in handy.

I cannot see why you would benefit from a registry backup for that one. A
fresh reinstall is recommended, and activation at MS thereafter.