Hello, 

 In those rare instances when you cannot reset the Samsung Jack SGH-i637 Smartphone from within Windows Mobile (recommended), do the following to manually reset the device to its initial settings: 

1.
With the unit powered off, Press and hold down the number “5” key.

2.
With the “5” key depressed, power on the unit.  Then, release all keys.  The hardware format menu will be displayed. 

3.
Tap the number “3” key to Master Reset the device.

4.
Finally, tap the “y” key to confirm your selection.  The unit will reset back to initial settings. 

Mark