Unhappy [Q] faild update

hey everyone , excuse my english iam still beginner.

i have i747 ATT and i was running on 4.2.1 , but i decide to get updated with 4.3 , i did download it and flash it but after doing all that the phone stops at setup screen showing nothing except apps has stop working example. unfortunately Samsung cloud data relay has stopped

please help and what i should do , thanks to you all