I had a well organized game client for my main account and everything worked just fine, until I decided to introduce a new account to the game.

At first my already installed addons weren't set for the new account and it was a complete mess (which is totally normal) I disabled them for each character individually and the new account was fine to play and setup.

The issue I'm having is that my Main account to which I haven't done any changes what so ever got completely obliterated, the UI is all messed up, addons don't load properly, disabling the addons brings back the default WoW interface but all my bar slots are messed up they became some sort of a mix between my Main account's character spells and spells and macros from the new account. Also all the settings regarding the game client got transferred from my new account to my Main one, including the key bindings. For example my main account wasn't set to Notify me when a Guild member comes online, but now it does, just like how my new account has that setting enabled.

I tried deleting Cache, WTF and it didn't help.
I remembered I have a spare game copy with my Main account in a different hard drive and when I logged to it my UI was still bugged even though the new account hasn't even been played on that game copy.

I don't know what to do, does any one have any idea what's going on?