It will remove all the data ,contacts and apps that you installed

Here's how you can start:
Solution 1
Key in *2767*3855# and dial it.
Solution 2
1. Turn off the device. If it is stuck then try to pull out the battery for a minute and then put it back in.
2. Press down the HOME key and the POWER button.
3. Then release the Power button.
4. Now a menu appear give you the options to Fastbook, Recovery, Clear Storage, and Simlock. Select Clear Storage. Use the Volume Down button to navigate the menu.
5. Then press and release the Power button.
6. Finally wait for your device to reboot.
Once the Samsung Galaxy Gio restarted it should now go back to the default factory setting.
Solution 3
This option of reset can be done via the settings menu. If your device is still operational, you could try this method.
1. Open Settings.
2. Select Privacy.
3. Choose Factory Data Reset.
4. Select Reset phone.
5. Finally select Erase Everything.
Samsung Galaxy Gio Restore Factory Hard Reset Format Phone.So lets start the Samsung Galaxy Gio Restore Factory, Samsung Galaxy Gio Hard Reset.Turn Off the mobile phone for few mints.Samsung Galaxy Gio Remove Pattern Lock.
Sign up here with your email
Restore Hard reset will set your phone in origional factorry settings. It will remove all the data and apps that you installed. Your contacts will be removed and you have to add them again.
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