In order to hard reset a Dell Mini 3i, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Dell Mini 3i device will be brought back to the default configuration of a brand new device.
1. First, turn on the phone.
2. Now press & hold the Volume Up + Power + Volume Down buttons until you see configuration screen.
3. Select the Factory Reset option - use Volume buttons to scroll and Camera button to confirm.
4. Unless you messed something up, your phone should now reset and restart. Woohoo, hard reset is complete!