This could help you but this will '''remove all''' your saved data and media from your phone.
* Turn it off and then hold '''Volume Down''' and Start the phone, keep holding the the buttons.
* Now you will come into to recovery menu.
* Use the Volume keys in order to navigate through the recovery menu.
* Select “advanced” and choose “wipe dalvik cache”.
* Return to main menu.
* Then select “wipe data factory reset”.
* Return and this time choose “wipe cache partition”.
* Return and select “reboot system now”.
* Your handset should start in Android OS now