I tried to upgrade my CPU (looking forward to Skyrim) and all the magic smoke got out

Anyway, got a hand-me-down and reinstalled Morrowind onto my old drive and then copied the old directory over the new
(thinking it would avoid reinstalling all the other patches, mods, etc). It seems to have worked - except that when I try to
uncheck all the various mods in Data Files in order to play the new Sword of the Perithia Plugin they won't stay unchecked!

Starting a new game still shows ALL the old stuff loading first. What am I forgetting, please?

edit: oops, forgot to mention that old drive and games were run on Win XP and new system is Win 7