Why is it it's always the hardest one to reach?
Can you get to the bottom of it? Sometimes there's enough to grab from there.
If there isn't any stud left and you can't get it from the bottom, it's drill time. Get a set of "Reverse Drill Bits" They turn the opposite direction from regular bits. You need a reversble drill motor too. Autozone and Sears sell the reverse sets for less than $10.
When you drill it with those and it "catches", often it'll screw the stud right out. Start with a small drill, then work your way up. Make sure you keep in straight.
Once the hole on the stud is good sized, often the stud will collapse and you turn it out with needle nosed pliers.
No matter what, it's always a PITA!!!!!!!!!!!