Yanking a power cord forcefully from a side angle could short the motherboard out, those connectors inside aren't that ruggedized. It's just a connector soldered onto the board, you can even wiggle some of them with or without the cord plugged in. Either something shorted on the board related to power or the socket came loose. If your willing try reheating the power connector with a soldering iron? Actually that is a high risk and I am leary recomending it if your not careful with heat, just a quick dab on each connector pin.

Since you were "playing" with the power supply, yanking it out could have jostled something and caused a splinter surge, but I would bet physical connector damage versus that scenario. In worse case the board got twisted a little and a run or 2 got crossed. Those things have many layers under the plastic coating, pretty spiffy.

My friend has the ALienware laptop, whew expensive but very "kick ass".

Dell sends me and my staff parts all the time. I bet they are leary at home based end users. The business division works a little different. To date this year I have reveived 3 motherboards, 3 hard drives and one laptop power supply. I had an issue where you have to wiggle the connector to get the power to go AC off the laptop battery. It turned out to be the power supply connector wore down enough to not make decent contact, versus a problem with the laptop itself.