The first place you should visit to unlock your Nokia 7160 Supernova is Nokia themselves at networks.nokia.com/about-us/contact-us.
To unlock your Supernova 7610, all it should take is the following:
- Switch off the phone
- Press and hold the green talk button
- Input +3+*
- Power the phone back up
For more details, check these sites which have user guides on unlocking this type of Nokia:
- mobifreedom.net/unlocking
- unlockallcellular.com
- gsmunlocking.eu/phone
If you need to perform a hard reset on your Supernova 7610, visit hardreset.info/devices/nokia to find out how.
This Spanish YouTube user claims to be able to unlock a Nokia Supernova 7610 in under a minute, why not try his method out, if you can keep up!