I recently purchased a 13-inch Haswell Retina. Shortly after updating OS X to v10.9.3, I was listening to music on YouTube (in Chrome) when the Haswell abruptly turned off. Unfortunately, I wasn't in the room at the time, so I don't know whether any error messages flashed on the screen prior to termination. I tried turning it back on, but absolutely nothing happened. Aside from the green light on the Apple 85W MagSafe 2 Power Adapter, the machine showed no signs of life. I've tried resetting the SMS and resetting the PRAM several times. In fact, I've tried both processes with the power adapter unplugged and with it plugged in. The Haswell doesn't respond in any way—no fans, no heat, no display. Do you have any suggestions?