Yet another moving an installation to another computer question

My Acer mobo just died, - a 1.2 GHz AMD, - and I need to transfer the 80
Gig HDD to another computer (a Gateway Performance 733 which had a 6 Gig HDD
on it which I propose to use as a slave, empty): I get an inaccessible boot
device BSOD which I kinda expected as I didn't expect the chipsets to be in
the slightest bit the same: Here is the question

I don't have the original install discs for the Acer and cant be bothered to
reinstall all the software, and there were some video clips which I hadn't
backed up which I want to keep. So I have a copy Windows 2000 install disc
which I was using to do SFCs on another Windows 2000 computer which came
with a recovery disc. I don't have any installation keys or codes for that
disc.

Is there any way of reinstalling the OS with some type of repair
installation which will preserve the product keys but change the chipset
recognition on the OS installation to whatever the Performance 733 has got
on it? I presume I cant get onto the HDD with any kind of boot disc so that
I can edit the registry to read the product key to preserve a legal
installation so I wanted to leave the presently legal product keys in place
rather than get a fresh set of illegal ones off the Internet

http://support.microsoft.com/direct...B;EN-US;Q315341
seems to involve putting in new product keys which would have to be illegal
ones which I am reluctant to do if there is a legal way of doing it.