Sounds like the last part of the thread has been damaged. It it spins easily that would be consistent with this theory. The only way I know is to get something under the edge of the head like you were trying to pry it out, then turn it at the same time. Perhaps a putty knife or if you have to a knife blade. It should not take a lot of pressure, just a little as you turn it. Once you get past the damaged threads it should unscrew. As a last resort, vice grips.

 

Thanks for the help.I did finally get it tonight.I was able to work out by slipping a screw driver under the egde and while applying upward pressure it came up slowly and out.Thanx again