There are a lot of reasons you may be facing the not registered on network problem . These are 1 Nulled IMEI Number 2 No Service 3 Unknown Baseband 4 Outdated Firmware 5 Radio is off You can check your IMEI number by dialling * # 0 6 # , you will see 0000 or nulled if it's corrupted. If you have an Unknown baseband then i suggest your to backup and restore your EFS Folder.This folder contains all the information about your phone. Simply go to settings , then go to about, then hit the update button.This will update you to an higher OS version If your radio is off , dial *#*#4636#*#* . Then click Phone Information.Run a quick Ping. After, Turn Radio OFF/ON I found all the information on - http://www.technobezz.com/fix-samsung-galaxy-registered-network/
