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I would personally suspect a battery issue from your description but I am kinda guessing since I have no experience with that model.
I did read that you can use that model without a battery if needed.
I did find this however which I think is a good thing to have bookmarked on a different computer - just in case http://forum.notebookreview.com/asus-gaming-notebook-fo...
I couldn't find a whole lot about your issue specifically.