If your mobile Oppo Neo 3 R831K gives slow speed of operating system compared to normal condition, then we can solve this issue by hard reset method. Pattern lock also be unlocked by this trick easily within five minutes. Before hard reset your mobile first take backup of important data on computer hard drive, because this will delete all data on mobile memory. you can also reset mobile via settings if you have remember your pattern lock, otherwise key combination is best method to hard reset the mobile phone.
1.Ensure the device is turned off.
2.Press and hold volume Down + power button until language menu appear. Select English press Power to confirm.
3.Android recovery menu will appear Select Wipe Data and Cache then press power button
4.Also select Format Data and Wipe Cache and power to confirm.
5.Select Yes option to format.
6.Select “reboot” and press power button
7.Wait until the phone restarts