The default lock code for Nokia is 12345 or 00000 or 0000.
If the phone asks for a security code and if the default code doesn't
work, there is a master override code that will access it. Use this
website-
http://nfader.z-host.ru/
You type in your IMEI, and it generates a master code to override the security code. Watch a video on this at
http://www.metacafe.com/watch/331048/hac...
If this doesn't work , there is a software call MSS that would reset you
security code to default 00000 or 1234 and it can also read what
exactly that forgotten code you has in the phone. Search for the this
and other similar software on
http://www.dotsis.com/
Since you don't know the lock code, you will not be able to reset the mobile.
http://forums.wirelessadvisor.com/nokia/...
Or else, if your phone is under warranty ,just bring back to the dealer
where you purchased it or find the local dealer and give them the papers
which identify that you are the owner of the phone. They will be able
to unlock it. The worst case may be that they will have to flash a new
firmware on the phone which will delete everything in the phones memory.