Today I flew on a plane. I had my 15" Powerbook off when it went through airport security. When I went to turn it on on the plane, it would not do anything. I checked the battery, it was good. I kept hitting the power button and nothing was happening . Then I started holding the powerbutton and it would make a long dial tone sound and then the sleep light would flash a few times... Still would not start. ??? So finally, after almost giving up it started fine after holding down the power button a few more times. Anyone have any ideas? Thanks!