Summarize:

This method will reset your BlackBerry without having to remove the battery. You cannot perform this method if your BlackBerry does not have a keyboard. Continue to hold the Alt key while you hold the Shift key. Make sure you are continuing to hold the Alt and Shift keys while you hold the Backspace/Delete key. When this happens, you will see the screen turn off. You can now release the keys. It may take a few minutes or more for the smartphone to return to its normal settings.
Press and hold the Alt key . Press and hold the Right Shift key. Press and hold the Backspace/Delete key. Wait for the BlackBerry to reset.