Fan Noise, Defective Fan, Vaio VGN-sz660n

I got this Vaio refurbished about 1 and 1/2 years ago and the first thing I noticed was that there was excessive fan noise. It was clrearly something defective, not regular fan noise. It sounded like it was scratching against something or out of balance. So I sent it back to sony while it was still under 90 days warranty and sony replaced the fan. It worked fine for a while but recently the noise came back. It sounds like the fan is out of balance because the noise comes on an off while the fan is running. I opened the laptop to take out th fan and inspect it and spray some wd40 on it, but one of the screws keeping the fan in place was worn out and I was not able to unscrew it. The sony repair techs probably did that. So I sprayed some WD 40 as much as I could in the fan and it sounds a bit better, but the noise is still there. The nosie seems to come on more in cold climate, and always comes on when I tilt the laptop a bit. I'm pretty sure it is a defective fan and not the fan causing vibrations of another component. So what am I supposed to do? I'm thinking of buying a new laptop because this noise is annoying, and makes it unportable because I can't take it to the library or coffee shop without annoying other people. I could pay $100 for a new fan, but the fan was already replaced once, so clearly these fans are defective and this issue will likely arise again in the future. Also, how would I unscrew that worn out screw? What should I do?

 

I called Sony and they refused to do anything about it, eventhough they failed to fulfill their original warranty obligation by leaving a worn out screw and making it difficult to service the vaio in the future.

Does anyone know how I might be able to remove this screw? I see commercials about devices for this purpose on TV but they are for large screws, not tiny notebook screws? Perhaps superglue the screw to the screw driver?