Try before formatting phone Nokia to do the following: turn off, remove, put battery and turn it on, then off and give the lie without battery for about thirty minutes. Turn on phone without memory card and SIM card. Turn it on with the charger.
If these steps did not help you, do a factory reset. This should be done only if other ways to revive your phone did not work and another way you do not have. Reformat before selling to be fully clear, or when it's very buggy. Reset to factory condition can help solve the problem.
Just dial code *#7780# to restore the original settings of the phone. Erased all settings Internet, backlight, display, but the information will not be lost. Save all the information that you want to use in the future, to the computer.
Then run the reset settings Nokia. To reset to the factory default settings use the code *#7370#. In this case, the memory of the phone will be returned to its original position, all the content (music, photos, pictures, messages) and apps will be deleted.
Use another method if the previous steps did not change anything either when the phone is not included. On / off phone, simultaneously press three keys: green (call transfer), and three star.
While holding these buttons, press the button on the mobile phone. Then wait until Boavista splash screen that says Nokia or message about formatting. This method also places the phone in factory condition - will be deleted applications, content and the file which stores the password of your memory card, if it has been installed. When prompted to format your phone enter the password the default is 12345.