I bought some caned air to clean the inside of my G5 and it was working all right but the metal plates underneath the Graphics card have dust that cant be sprayed off. So i was like okay ill take the gfx card out and it will be easy to wipe off. So i start unscrewing the front philips screw and it was sticking to the screwdriver fine when it fell in to the abyss.(back Fan) I cannot get it out i laid on my back with computer upside down. Then i said whatever the gfx isnt going anywhere i pluged it in and everything is normal. But can that screw mess things up?. I think its behind the mother board. In any case i had my sub by the tower and it vibrated loose... wink wink cough apple care.