Ok so today my Alienware 17 turned off while gaming suddenly. I tried to turn it back on but I noticed the blue led light on the power cord was not on. I disconnected it and unplugged it from the outlet and back in and the light came back on however whenever I try to plug it into the comp it goes back off. Apparently I used up the battery because the computer will not even try to power on. So I got my old Alienware 17xR2 and plugged the cord in and it works fine. I even swapped the 2 cords...
Alienware 17 Power connector/mb problems
Alienware 17 Power connector/mb problems