WHEN YOUR CELL PHONE DOES NOT RING....................? A:RESTORE FACTORY SETTINGS

WHEN YOUR CELL PHONE DOES NOT RING................/WHEN YOU CANNOT HEAR YOUR RINGTONE WHEN YOU RECIEVE A CALL............? 

then you just have to RESTORE FACTORY SETTINGS:
1.go to your setting in your mobile
2.there you will find  RESTORE FACTORY SETTINGS
3.when you click on it ,it will ask for the password
4.enter the password and you will find your mobile working again :)

*NOTE:1.When you restore factory settings it will ask for a password even though your mobile don't have one,but dont worry .UNIVERSAL CODES(every mobile has one) will just do fine.

eg:universal code or DEFAULT SECURITY CODE for   

   NOKIA:12345   

  GFive:1122     

SAMSUNG:00000000
2.when you forgot your password or your cellphone might ask for a security code when u actually never put  code for your mobile,then default security code might help 

RESTORE FACTORY SETTINGS:(source: wikipedia)                               

A factory reset or master reset is a full restore of an electronic device to its factory settings. Such electronic devices include handheld computers such as PDAs and cellular phones. It entails deleting all information stored in the device. This is essentially the same asreformatting a hard drive. A factory reset may become necessary from time to time on a device which is no longer working. It should be used with caution, as it destroys all data stored in the unit. Many problems with a hand held electronic device such as freezing can be resolved by performing a factory reset or hard reset.