Help please How to remove stripped screw ?

I have received a Audio Note M3 preamp last Friday. I have been searching for it for quite a while before I found this decent unit. Needless to say, I have been listening to it in my system over the entire weekend.
Tonight, I tried to open up the unit so I could see the components inside. To my surprise I discover that one the screw has been stripped by the previous owner. Is there any good ways to remove the stripped screw without scratching the preamp?

I would hate to have to send it back to the factory just for a stripped screw. But I would hate it even more if I scratch the preamp.

Any help would be awesome.