I'm playing from Beta and always had such problem.
The game "freezes", I can run, I see all chats but I can do nothing and all the world around stopped. Also there are a lot of Unknown errors while playing..
I tried to reinstall the client, repair it, reinstall my windows, change settings by "low", update all drivers and so on..
Nothing helps.
Does anybody have such problems and what can I do? ESO support didnt help..