Select Shutdown my computer radio button if you want Power key to act as usual.
If you want Windows to ask you what to do when you press Power key, select Ask me what to do radio button.
To block Power key completly, select Do nothing radio button.

You can make I Hate This Key to block Power key completly, but enable it when some modifier key pressed along with Power key.
Select Act as usually if I hold these keys while pressing power keys check box and then select appropriate check boxes for modifier keys.