Ive not tried this one... so it is AT YOUR OWN RISK! It seems similar to accessing the recovery menu I think.
To do a manual reset:
Hold the volume+ button for ten seconds, whilst still holding it press and hold the on button until an android icon appears.
When you see the android icon press the home button.
Use the + volume button to navigate to the factory data reset option then use the - volume button to select.
Then select reboot device.
Done