You can lock your nokia cellphone, standard code is 12345, you can change the lock code (security code).
Lock code protect your cellphone from wrong hand or to keep your data save from other person.
How to set Nokia lock code ?
You can enable your nokia cellphone to prompt you for the code every time your turn the cellphone on, or wake it from standby mode.
To set lock code: Menu, Tools, Setting:General,Security,Phone and simcard, select Lock code.
Entry the old code and input your new code, twice for verifying.
How to reset Nokia lock code?
You need old code to reset lock code, how if you do not remember the old code?
The thing you need to do is reflash your firmware, or set setting back to default (need repair tool box : like Jaf, or Ufs3), other ways go to nokia care center, or calculate your code online.