First turn on the phone, select "Settings" as shown in
In the Settings column, select more Settings
In more settings, you can see "Restore factory Settings" to open this item
In the "Restore factory settings" Item you can see two options to first introduce the ① "Restore all Settings" ② "Erase All data" in the bottom diagram
① "Restore all settings" This restore is all the settings for restoring your phone's settings, but will not remove any other data, just restore settings such as ringtones, screensavers, and so on.
② "Clear All data" This is the merger above "Restore all settings" at the same time, will completely remove all the data in the phone, is restored to the factory appearance.
At this point, want to restore the factory settings must be considered clearly Oh! All the data was erased when pressed. If the system is only a bit of a problem, the kid suggested that the first switch machine to try, and sometimes the phone has long time no switch machine, the system for a long time standby or frequent use will be a bit of a problem, the boy tried to deal with the switch machine. The system is back up and there is no more problem.
If this does not work, then you can also carry out mobile phone system upgrades, the specific steps, as shown in the following diagram.
"More Settings" select "Check for updates immediately" when you enter the above "system upgrade" to check for a new version, have the option to update the system when there is a charge of over 60%.
In the update system can not handle what you think of the system problem, you go back to the factory settings!