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Please do not cross post as it wastes time and effort.
Other post deleted.
You might want to take a little time to read the posts at the top of the forum sections as they detail how best to use the forum.
It was probably a voltage spike, or maybe static electricity, but sounds like the board is fried if the lights don't come on, and the computer can't recognize it. most of the time either the voltage regulator fries or a capacitor dies. I've never had that happen with my arduino yet, but i've experienced it several times with my computer motherboard.
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I hope you are not attempting to use the Mega powered via its "Barrel jack" or "Vin". The on-board regulator is essentially decorative - for serious use you need to supply 5 V to the "5V" pin or the USB port.
So it does nothing when simply plugged into the USB port?