I tried taking it off (by un-equiping the individual pieces), but can't rest because "I cannot do that in power armor". Then I dropped all the pieces of power armor; they are on the floor at my feet, and no longer show in my inventory... but when I pan back to see my character, he's still standing there in power armor!!

I tried pressing A, B, P, and other keys that peope suggested in various places, but just can't get this to go away!!

Had the same problem. Google said i should hold down the button i used to get in (activate). That kinda worked for me.

Long press your interact button

Have you tried holding the activate button? On controllers it is the A or X button respectively. And I think it's E on Keyboards. Just hold it down in an open spot.

Well, I'll be danged... yes, that worked...

When I tried before, I must have neglected to "hold" the button (which is 'E' in my case, on PC)...

Thanks!!!