Hmmm... I reinstalled Windows, downloaded the addons again to C:\Users\patri\Documents\Elder Scrolls Online\live\AddOns, but the game client does not find the addons.
If you're on Win10, it is (if OneDrive activated) in your OneDrive folder.
If you don't find anything, just search file UserSettings.txt on your whole disk.
Obsessive Compulsive Elder Scrolls addons Coder
A Few millions downloads of ESO addons now. Master crafter on my main char since release. All tradeskills, recipes \o/, researchs (since long), 35 styles known
My little french Guild: Cercle de l'Eveil