Trouble Shooting Power Issue

Hello All,

I have an Alienware 14 2013 model....

I recently noticed that the battery was not fully charging...  Then after running a battery diagnostic, I tried to reconnect the power supply and when I plugged it in, the blue light on the plug went out.  Now, every time I plug the power unit in when the battery is low and the laptop is on the blue light goes out and no power is supplied to the computer.  In order to get the unit running with a low battery the computer must be off, then plug the power cord in and then the blue light comes on and will charge the battery and eventually start up.

When the battery is low, like now, the power button changes colors from Orange, to red, to green and then repeats...  I can't tell if this means the battery is bad, the power supply or God forbid something on the main board....

Please Help!!

Thanks...