conect your nokia phone to computer

 Download diz software to ur pc :

http://download.cnet.com/Nokia-Software-Updater/3000-18511_4-205052.html

connect ur mobile to pc vid usb cable and den click on above software it vil show u wich is latest version available and it vil ask u to update and u can update...

But firstly backup all ur data to memory card and remove memory card and do above process...