In order to hard reset a Dell Aero, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Dell Aero device will be brought back to the default configuration of a brand new device.
1. Turn the phone on.
2. Starting from the Home screen, open Settings > Master Clear & Reset > Master reset.
3. Type in the Master reset password (1234 by default).
4. Tap OK. The device will now reset. Done!