Reset HP N70

i have HP nokia N70 and i have experience with this HP. the problem of this HP is if i get any call or sms the ringtone doesn't want ringing so if i get any call i don't hear anything for that HP . so i decided to reset its HP. so how to reset this kind of handphone.

The way to be done to restore these settings are as follows:

• dont forget to Back Up data in the phone memory, as restoring will cause all data on phone memory will be erased.
• Type * # 7780 #
• Appears to confirm whether the process will be continue, type "yes" / "yes"
• Confirmation appears and then just type "12345"
• the setting will be bact to pabric setting and the error is gone.