I need to reset a nokia 2126 tracphone to factory settings someone had locked it and dont know the code

check this one

Master Code Generator will Instantly generate your Nokia's Master security code.
This service can be used if you need to reset your Security Code.
Your IMEI: 356924034968264 --
Your Nokia Master Code: 2401254345


or this one


Nokia 5000 hard reset
You can format your Nokia 5000 device by typing: * + 3 + call + Power on. Before the device is reset, you need to provide the lock code. The default lock code is 12345.
If it is not working try this code:
You can format your device by typing *#7370# in standby mode. Before the device is reset, you need to provide the lock code. The default lock code is 12345.
Some Nokia phone can be reset via this menu option
Press menu button or enter Menu > Settings > Phone > Phone management > Factory settings > Delete data and restore > YESRestore factory settings
To restore the phone back to factory conditions, select Menu > Settings > Rest. factory sett. and from the following options:
Restore settings only - to reset all preference settings without deleting any personal data
Restore all - to reset all preference settings and delete all personal data, such as contacts, messages, media files and activation keys
IMPORTANT!
Formatting the device will permanently erase all user data and settings as well as add-on applications and operator specific settings
goodluck

Nokia 5000d hard reset
You can format your Nokia 5000 device by typing: * + 3 + call + Power on. Before the device is reset, you need to provide the lock code. The default lock code is 12345.
If it is not working try this code:
You can format your device by typing *#7370# in standby mode. Before the device is reset, you need to provide the lock code. The default lock code is 12345.
Some Nokia phone can be reset via this menu option
Press menu button or enter Menu > Settings > Phone > Phone management > Factory settings > Delete data and restore > YESRestore factory settings
To restore the phone back to factory conditions, select Menu > Settings > Rest. factory sett. and from the following options:
Restore settings only - to reset all preference settings without deleting any personal data
Restore all - to reset all preference settings and delete all personal data, such as contacts, messages, media files and activation keys
IMPORTANT!
Formatting the device will permanently erase all user data and settings as well as add-on applications and operator specific settings
goodluck

As far as I know there are two possibilities to get this error message.One is poor signal of that respective network for which you just need to switch OFF and ON your mobile and the mobile will be able to receive the signal from near by tower.You may also get this error message when you are trying to insert a sim other than which the mobile is locked to.To solve this problem you need to unlock the phone from that particular network or use the same sim to which the mobile is locked to.. You can unlock Nokia 2126 using unlock code, You can purchase such code from any vendors online like
Mobile-Unlocker.com

goto menu n settings last setting is factory reset seting

Sir/MamFor your preference click here
Thanks for using FixYa!

For restore the Nokia 2700 Classic Mobile from the security Lock,you need to use the Master Reset Code,You can get the Master reset Code at reliable cost at here
http://www.superunlockcodes.com/nokia-2700-classic/rs12wp9/

ou can get the master reset code for your Nokia model mobile, through this site http://www.theunlockarena.com/nokia-dct-master-code-service/rs13wp10/
It has the best services for the master reset codes and unlocking codes for mobile phones.........

When phone is off try using this key combo: on/off + * + 3

reset this phone to factory setting by *#7370# and make sure it's on charge..Code should be restored to factory setting.Hope this helps..

either *#7370# fro the standby screen, and enter lock code, default is 12345

or when booting up, hold the call (green) key, 3 and *

alternativly try reset to factory from tools>settings>general>factory settings.. again default lock code is 12345