Master Reset For Mobile handset..

IMEI for All Mobile Set:
 *#06#

Master Reset For Mobile handset:
For lava:
4321
For SAMSUNG:
*2767*3855# or #*7728#
*2767*5282# Java reset and (deletes all java midlets)
*2767*63342# Reset media (deletes all sounds and pics)
*2767*927# Wap reset

For  VIDEOCON:
 2945#*88110#

For LG Mobile:
LG all models test mode: Type 2945#*# on the main screen.
2945*#01*# Secret menu for LG

For NOKIA:
*#7780# or*#7370# and default code 12345