LG A100 hard reset
To bring up Factory mode key in this code 1809#*100#
To reset your LG A100 phone to factory settings and erase all the data on your phone, Select Menu > Settings> Factory default settings
Reset settings (Menu > Settings > Reset settings) – Use Reset settings to restore the factory settings. You need the security code to activate this function. The default number is “0000”.
Only Menu...Settings...Factory reset....code 0000... If not ok with this need re install full software.
You can use LG Mobile Support tool to repair your LG cell phone, after download select menu Customer Support > Recovery Phone