Phone playing up?
If your Galaxy Ace keeps freezing, you’ve forgotten the security codes or it just doesn’t work, take it back to factory settings.Important: This wipes everything on your phone, so if you’re not locked out try backing it up first. This won’t wipe your SIM.
Switch the phone off. If it's frozen, remove and reinstall the battery to turn it off.
With the phone still off, press and hold the Home, Volume Up and Power buttons all together until you see the Android developer menu appear (as seen in Step 2).
Use the Volume Down key to scroll to wipe data/factory reset and then press the Home key to select it.
Use the Volume Down key to scroll to Yes - delete all user data and then press the Home key to select it.
Use Volume Down to highlight reboot system now and the press the Home key to select it.
The phone will then reboot to its factory settings.