I decided on cleaning my laptop fans today, which I've been procrastinating for about a year now because of this one screw. But I just can't seem to open this with my screwdriver, since whatever I did back when I last opened it it's nearly circular now. Is there a way to unscrew this?
Maybe try using a file to make flat sides on the outside of the head so you can use a wrench on it? (Not sure if that would be better or worse than the Dremel/slot idea... you would risk scratching the surface of the object it's on.)