Weird Latitude CSX standby problem

While trying to get the hard drive and caddy out of one of my Latitude CSX laptops, one of the screws came off and went inside the laptop. I shook it around and could hear it bouncing around inside the laptop. I kept trying to get it out and the noise stopped so I figured it came out, but I couldn't find it. Later, when I turned on the laptop, the display would go black now and then. I kept starting the computer, sometimes on top of another Latitude CSX and sometimes on a table. I thought maybe the screw was still inside the laptop and was causing this problem, so I opened it up and found the screw inside the laptop. After turning it on a couple times, I noticed I still had the problem. Sometimes the laptop would say it was going into standby mode. I finally figured out that this only happens while its sitting on top of the second Latitude CSX. Is it possible that the CSX that is turned on and put on top of the other CSX is sensing the display of the CSX below it (its not turned on) and thinks its being closed (display closed against the body), and then goes into standby mode?