In order to hard reset a Haier N90, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Haier N90 device will be brought back to the default configuration of a brand new device.
1. Hold down the Power button to turn the phone on.
2. Go to Settings > Restore Factory Settings.
3. Your phone will now reboot and restart. The hard reset process is complete. Grats.