Before you buy a new cell phone or new tablet, please try the following procedure to repair your device. First charge your battery, backup your important data if possible and in most cases take out SIM and SD card before factory reset. It is impossible to recover your data after doing a hard reset, so online backup is always important. For all of your data, a backup should be done on an external device, hard drive, raid system or media. With or without insurance, if your cell phone lost, damaged or stolen at least your invaluable data is backed up in a safe place. If you are about to sell your phone and you want to wipe your personal data, or if your phone affected with virus you have to do a hard reset. In some cases, you can delete the forgotten password or lock pattern from your device as well. All information is for devices with stock based ROMs. If you are using rooted device, always back up your EFS folder first, containing your IMEI info, etc.!
If it does not restore to the original condition, use hard reset to initialise your phone.
When the phone is turned off, press and hold the Home key + Volume down key + Power key
for over ten seconds. When the screen shows the LG logo, release the Power key.
After the screen shows the hard reset screen, release the other keys.
Leave your phone for at least a minute while it performs the hard reset, then your phone will be turned on.
Caution: if you perform a hard reset, all user applications and user data are deleted. This cannot
be reversed. Remember to back up any important data before performing a hard reset.
To reset your LG Optimus Net Dual phone to factory settings and erase all the data on your phone, touch Menu > Settings> Privacy > Factory data reset > Reset phone.
You can use LG Mobile Support tool to repair your LG cell phone, after download select menu Customer Support > Recovery Phone