Where is customization kept?

About to repurpose a WinME computer by installing XP, a couple of large hard
drives, max memory and a new power supply and fan. However ...

My son had done quite a bit of customization of the UI, with different
background images for many folders and specific lettering choices, color
choices, icons, etc. Is is possible to backup just those files, and if so,
which ones.

If he ever wanted to go back and reminisce, he could load ME into a virtual
machine and add the backed up files or replace the new, uncustomized ones.

Is this nuts? or is it do-able?

Thanks

2/4/06