In order to hard reset a Samsung J750, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Samsung J750 device will be brought back to the default configuration of a brand new device.
1. Start by turning on the phone by pressing the Power button.
2. Now enter this code into the phone: *2767*3855#. Confirm it using the Call button.
3. The hard reset process will be complete after your phone resets and restarts.