My galaxy s3 keeps re-booting after install a recent AT&T update
So I tried @Sjharrison's way to press home,power and volume button at the same time to put phone in recovery mode. And it gives me the option to safeboot my cell phone and I chose to delete the cache files. It automatically reboot and show progress on automatically installation. Then my cell phone works as before. Kudos on @Sjharrison!