I just finished setting up 10 laptops for new managers. I hate this process, but it is much faster now since I figured out how to get one exactly right and then clone a disk image onto a usb hard drive. I can then boot the new computer with a recovery disk and apply the disk image.
Anyway, there was something wrong with two of the installations. Symantec had server issues all this week and two of the PC's simply would not sync with their servers, probably because I set them up at the heights of their issues. So I had to pull them out, and do the uninstall-reinstall thing on the virus software.
But the very first laptop did not work -- it was coming on but its screen was blank. I pulled another out of the box. Same problem. And again.
Panicking I changed the power supply, checked the power outlets, and everything else I could think of. I finally called Dell in a rage.
Before they could really even pick up the phone, I happened to tilt the computer. The screen came on. I lifted it up in the air. Worked fine.
I finally figured out that I was sitting the laptop on top another closed laptop (of the same model) I had been working on. The bottom laptop was powered down, but it turned out that something was causing the laptop on top of it to have its screen not work. I can only guess it was some magnetic thing from the battery charging apparatus, since that was the only thing that was likely energized in the other laptop.
Anyway, problem solved but I never would have guessed that stacking laptops would make them not work.