I have a thought.
Any core changes I made I can identify because I made backup files of the originals. And of course, all the modules I installed, as well as all the content I created is still in their respective subdirectories.
If I go in and backup all the changed core files, reinstall xoops, reinstall the changed core files, and just reinstall all the modules from the modules page, the content should still be there shouldnt it?