Arduino board not detected

Ok, Little bit of background here: I’m building a 3d printer, based around a teensylu, a sanguinololu variant, and the prusa i3 design setup.

I had the printer plugged into my old toshiba satellite, since I figured if the printer has to stay tethered, I can use my old (>5 yrs) laptop to host while I go to class with my newer dell. However, a few minutes into figuring out repetier-host,the program that feeds each slice of the model into the printer, the toshiba died out of nowhere. I tried to boot it back up, but all I got were the fans; the screen stayed black and none of the lights came on. I’m thinking, it couldn’t have been the printer, since a usb connection couldn’t carry enough power to fry a laptop, but if it was just the old satellite giving out, that was preposterously terrible timing. I took it to geeksquad after trying to revive it for a few hours, and they agreed with my prognosis of death by old age. So that’s out.

So, this morning, I tried to connect the printer to my newer laptop, a dell running windows 8.1, but now the printer isn’t being detected. It had connected last week when I was fiddling with the bootloader, but now, not a blip. Not under the device manager, not even the “device connected” noise. The board IS getting power, since the light is on, but won’t respond to my computer or the old desktop.

First thing I thought to try was the cable. Luckily, my HP printer uses the same A to B usb cable, so I used that to connect my laptop to the board, nothing. I tried using the first cable to connect to the HP, and that worked, so it’s not either of the cables.

I checked over the board thoroughly, nothing looks fried or shorted or out of place, so honestly I’m at a loss as to how to move forward here. Mystified, I tell you.

Any advice or things to try would be appreciated.