For Samsung I9190 Galaxy S4
You can try the following:
1. Restart the phone;
2. Uninstall recently installed third-party software, reboot the phone;
3, after the backup phone data (phone book, SMS messages, multimedia information, etc.), restore the phone to factory settings: Set - Privacy - restore factory settings;
4, in my equipment, the main screen mode, choose Easy mode re-election back to standard mode.
If the problem persists, it may be a system or hardware problem, we recommend that you experience this problem, contact a Samsung Service Center friends for testing, in addition to green tea Xiao Bian also remind you please do not restart the phone when to press the Menu key, because the press safe mode enables live the Menu key.