All, Beginning last night my Mac Air would suddenly no longer get any power from its standard adaptor unless I shut down the unit completely. (Note: this is different from times when the computer might say "not charging" but the magsafe light is amber and at least the battery is not running down). At times I would down and the light woudl remain off--only after I unplugged the adaptor from wall and PC and then replugged after a few minutes did it resume charging. Finally today for a time I could not get the PC to charge my any means...so I unplugged everything again. Then, after waiting a few minutes I plugged back in and charging resumed, including after I powered on! There has been no water damage and the unit was bought new in April 2012 (just before the 2012 refresh). Any ideas?