Hi what kind of lock code are you asking for? Is it a phone lock or a network lock?
If it is a phone lock, You must do a master reset for your Nokia 7610. This could restore your phone with default factory settings.
If it is a network lock, You need to enter the unlock code. You can get the unlock code either from your network provider or from any trusted vendor online. For example you can get the unlock code from www.unlocking4u.com/nokia-7610-supernova/rs6wp9/
at affordable cost.
Here are the steps for unlocking a Nokia 7610 SUPERNOVA,
1 - Switch on your Nokia 7610 SUPERNOVA without
any sim card.
2 - Don't bother as to what is displayed on your Nokia 7610 SUPERNOVA.
3 - Compose #pw+CODE+1#
4 - The Nokia 7610 SUPERNOVA would then display the message "SIM Restriction Off" and will be unlocked!