Hi, I've taken my iMac from Finland to England by plane, and while travelling everything seemed to be fine. But now if I try to turn the computer on I can hear the sound of turning on but the screen is still grey and nothing happens. What could I do? I don't have an idea what could be the reason because the iMac was well packed and the screen seems to be completely unharmed from outside. Please tell me if anyone has any tips!