There are two kinds of damage to the white lcd nokia 6120c, namely software and hardware
Damage software nokia characteristics when phone on, Phone on just for while and then die, it is because your software is part cnt.just flashing part of his or rm243_ENO_A_2009wk15v0.100.fpsx ppm cnt same mcu, also no problem.
be sure to use a new LCD, connectors check if there are still white resisstensi value of his guns every point connector. Under the picture, just a red dot that no value resisitensi
If still white srceen,you must replace two ic below image