Phone just stopped working propertly.

[Rodrigos GamerVids]

After i installed latest android on my LG-G3 it began to be slow and kinda laggy. but today i cant even use it anymore. when i turn it on the loading screen seems fine. but when it has to show me home screen it pops me up a log wich says ''Unfortunately, Setting has stopped''. i click on and it keeps popping up, and switching screen colors. Behind that ir shows me an error ''can't find matched cust for NT-code mcc/mnc[], subset[]''. what should i do? i tried to hard reset phone but it doesnt help at all.