Seemingly Serious Problem Updating to MS2 v2.0.6 in Melco N1Z/1 [SOLVED!]

[GreenMtnGringo]

So I hit the Power button to try to power down the Melco and ... nothing happened. The unit stayed on and the "Install in Progress" message is still stuck on my Melco display. In several years of owning this Melco the Power button has never failed to turn the unit off. Now I am really worried, as the only thing I can think of to do at this point is to pull the AC power cord out of the back of the unit. I really do not want to do that, but none of the buttons on the front -- including the Power button -- are doing anything.

Simon, please help, thanks.

EDIT: It is 11:25 PM ET and I am logging off for the evening. I will reluctantly leave my Melco on overnight with the "Install in Progress" message on the display (with no way to dim it). Simon, if you see this thread, can you please post a message as to whether I should pull the AC cord out of the back of the Melco, or what? Thanks.