LG C800 hard reset

If you can’t recall your C800 unlock Pattern:

When the phone is turned off, press and hold the Power/Lock + Volume Down + Qwerty F + Qwerty A Keys at the same time (for over ten seconds).
The phone will turn on and perform a factory reset immediately.
WARNING: If you perform a Hard Reset, all user applications, user data and DRM licenses will be deleted. Please remember to back up any important data before performing a Hard Reset.

or
if you forgot the LG C800 Unlock Pattern
How to perform a factory reset:
1. Turn the power off.
2. Press and hold the following keys at the same time for 15 seconds: Power/Lock Key + Volume Down Key.
3. When the LG logo is displayed, release the keys.

When you perform a factory reset, all user applications and user data will be deleted. Please remember to back up any important data before performing a factory reset.

LG C800 hard reset
You can use LG mobile support tool and choose recovery mode.

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.