No power, no lights but green light on power supply blinks rapidly

Hi,
I picked up this Alienware 5700 off ebay to hopefully refurbish for my son but I'm new at this and still learning and so this thing has me baffled. The laptop is in pristine condition but shows no signs of life. When I plug in the power supply the green light on the power supply goes from solid green to blinking rapidly to the point you can barely see it. To me that would mean a short somewhere right ? If so where ? Has anyone else ever had experience with something like this ? I just don't want to go buying a new battery for a laptop that maybe fried already. Any help would be greatly appreciated.
 
Remove the laptops battery and try the AC power only. If the green light does the same, it still could only be a bad AC adapter, or at worst, a shorted laptop motherboard
 
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