It will remove all the data ,contacts and apps that you installed
Using the hard reset aka factory reset Optimus L5, resetting LG E610, reset LG E612
When the phone is switched off, press and hold the Volume down key + Power key with your left hand.
When the LED on the bottom of the phone lights up, release Volume down key + Power keys and press and hold the Home key (for about 2 seconds) at the same time.
The phone will turn on and perform a factory reset immediately.
Do not operate your phone for at least a minute, while the hard reset is carried out.
You will then be able to switch your phone back on.
If you perform a hard reset, all user applications, user data and DRM licences will be deleted. Please
remember to back up any important data before performing a Hard Reset.
To reset your LG Optimus L5 hard reset phone to factory settings and erase all the data on your phone, Select Settings → Back up and reset→ Factory data reset → Reset device→ Delete all.
Resetting the Andorid phone does not erase any system software updates you have downloaded or any files on your microSD card, such as music or photos. If you reset the phone in this way, you are prompted to re-enter the same information that you did when you first started Android.
You can use LG Mobile Support tool to repair your LG cell phone, after download select menu Customer Support > Recovery Phone
LG Optimus L5 Restore Factory Hard Reset Format Phone.So lets start the LG Optimus L5 Restore Factory, LG Optimus L5 Hard Reset.Turn Off the mobile phone for few mints.LG Optimus L5 Remove Pattern Lock.
Restore Hard reset will set your phone in origional factorry settings. It will remove all the data and apps that you installed. Your contacts will be removed and you have to add them again.