Sometimes it's best to drill the heads off the screws to release the hinges. Don't go too deep, or it gets difficult to remove the remaining piece of the screw. Of course, if the nut is spinning, it's probably going to be necessary to replace the whole assembly anyway.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!