[Overdriven]

Three options.
1: You can try a screw extractor, they are available at many hardware stores.
2: Use a cutoff wheel in a dremel to cut a slot in the head of the screw so you can use a flatblade screw driver to turn it.
3: This is the "if all else fails" option. Drill just the head of the screw off. Using the right size bit and going just deep enough is key here. Because you want to leave as much of the shaft of the screw behind as possible so you can grab it with a pair of pliers and turn it out. Compare a screw of the same size with your drill bits and use the largest one possible. This will help ensure you drill out the head first before the shaft of the screw.

I assume you meant locktite (or another thread locker) not lock nut. If thats the case, heating the screw with a lighter will help release the screw. I would do this before attempting to turn the screw with any of the above methods.