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.
or
Go to Menu -> settings -> privacy -> Factory data reset - reset to factory settingsor
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.