LG Optimus Chat C550 Android hard reset

LG C555 Hard Reset (C550 Factory Reset) If it does not restore to the original condition, use Hard Reset to initialise your phone.
If user turns on the phone with pressing and holding Power/ Lock key + Send key + Volume Down key at the same time
(for 10 seconds), the phone will turn on and perform hard reset immediately.
Please note, after you perform Hard Reset, all your data and applications on your phone will be erased and cannot be reversed.

LG Optimus Chat C550 hard reset

or

Go to Menu -> settings -> privacy -> Factory data reset - reset to factory settings

or

You can use LG Mobile Support tool to repair some LG cell phone model, after download select menu Customer Support > Recovery Phone

If your LG C550 hang up or has freeze problem First Remove and re-insert battery.
Turn on the phone. Try to do a software update service via WEB site or try hard reset using buttons.

General advice: Before you buy a new cell phone or new tablet, please try the following procedure to repair your device in a software way. First charge your battery, backup your important data if possible and in most cases take out SIM and SD card before doing 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.! Please also note, that a hard reset operation will not unlock your mobile phone's SIM lock or network lock, but it will remove the unlock pattern, remove the user password or PIN password (NOT the SIM card's 4 digit PIN code). Also note that the firmware version will not be affected in any way, it will not be downgraded, it will remain the same you are using and if you have rooted your device, root privileges remain also unaffected.