I have a nokia 5310. When I insert my Airtel or BSNL sim ( my old sim which i have used with this phone for the past two years ) it works fine, but when I use my vodafone or aircel sim ( which are my new sim to the phone ), the phone is asking for a security code ! I tried all the codes that I have known, but some how I couldn't figure it out ! Please help me ? I know " nokia care " can surely help me for the money that I pay but I am looking for a free fix from fixya ;-)

Hi

you are installed a security code when you are using your old sim cards

so if you wont to install a new sim card you have to know your security code

other wise

1) insert your old sim card
2) switch on the phone and back up all data
3) Connect your phone to pc using Nokia PC Suite and Data cable
4) make sure about your data
5) Download the Nokia Software updater
6) Update your phone software or reinstall if you have already latest software

if any doubt replay me

Link for nokia Software updater
http://www.nokia.co.in/support/product_support/phone-software-update