What is Factory Reset of Android Mobile
It removes all USER DATA and restores the device back to factory settings providing that the device is not rooted. User data is defined as apps, call logs, contacts, and anything else the user has placed in the devices memory. Stuff that is on the SDCARD is not affected by a factory reset. By performing a factory data reset, all data — like your apps, photos, and music — will be wiped from the device. Any data stored in your Google Account will be restored when you sign in, but all apps and their data will be deleted and cannot be restored.
Samsung Galaxy Ace Duos S6802 hard reset
1.Turn off your phone
2.Press together volume up + home button + power button
3.Browse with volume buttons and select "wipe data/factory reset" with home button
4.Select "yes" and press home button
5.Select "reboot" after format is complete
6.Wait until the phone restarts.
Hard / factory reset Samsung Galaxy S Duos S7562
1.Turn off your phone
2.Press together Volume up + volume down + power + home button.
3.Browse with volume buttons and select "wipe data/factory reset" with home button
4.Select "yes" and press home button
5.Select "reboot" after format is complete
6.Wait until the phone restarts.
Hard / factory reset android MOTO-G
1. Touch 
2. Touch Settings
3. Touch Backup & reset
4. Touch Factory Data Reset
5. Touch Reset Phone
Hard / factory reset android Lollipop
1. Ensure the device is powered off, and unplugged
2. Press and hold the Volume Down button and Power button (located on the right edge of the device) for approximately 3 seconds then release.
3. From the "Boot Mode Selection Menu" screen, select Recovery.
Note: Use the Volume Down button to scroll through the menu options and the Volume Up button to select.
4. From the "No Command" screen (Android figure lying on his back), press and hold the Power button then press and release theVolume Up button to display the menu options.
5. Select "wipe data/factory reset".
Note: Use the Volume buttons to highlight and the Power button to select.
6. Select Yes -- delete all user data.
Note: Allow several seconds for the factory data reset process to complete.
7. Select reboot system now.
Note: Allow several minutes for the reboot process to complete.
Hard / factory reset android Lollipop KitKat
1. With the phone powered off, press the VOL DOWN KEY for 2-3 seconds then POWER key then release.
2. The device will display different BOOT OPTIONS
3. Use the VOL DOWN Key to SCROLL to Recovery and VOL UP Key to select
Tip: If the device reboots, you may have waited to long to make a selection, you will need to begin the process again.
4. The device will display the Motorola logo and then the Android in distress ( logo with Exclamation mark)
5. Press and hold the VOL UP key for 10-15 seconds. While still holding the VOL UP key tap and release the POWER key
Tip: You can try this step, holding the phone in landscape. If you are stuck on step 6, try a force reboot by pressing the Power key and Vol Down key, and start the process again.
6. The device will display additional menu options (Text will appear in BLUE)
7. Use the VOL DOWN Key to scroll to Wipe data / factory reset and the POWER Key to select this option
8. Use the VOL DOWN key again to select YES - delete all user data and press the POWER key to CONFIRM
9. Once the Formatting is complete, press the POWER key to confirm a REBOOT
10. The device will reboot and start the normal power up sequence.
