I would like to clean-up old computer for my son. It had Windows Me on it
originally and I upgraded it to XP. Since it was an upgrade does that mean
I have to restore it back to the ME and then upgrade to the XP again?
No.
The requirement to use an upgrade version is to *own* a previous
qualifying version's installation CD (with an OEM restore CD, see
below), not to have it installed. When setup doesn't find a previous
qualifying version installed, it will prompt you to insert its CD as
proof of ownership. Just insert the previous version's CD, and follow
the prompts. Everything proceeds quite normally and quite
legitimately.
You can also do a clean installation if you have an OEM restore CD of
a previous qualifying version. It's more complicated, but it *can* be
done. First restore from the Restore CD. Then run the XP upgrade CD
from within that restored system, and change from Upgrade to New
Install. When it asks where, press Esc to delete the partition and
start over.