I agree with Akiko here as the error messages (as far as I can remember) are output to the Caps Lock LED - not the Power LED. Incidentally, my power LED flashes too - but that's down to a faulty LED.
Have you connected your audio up? One of my A600's PSU's went faulty which resulted in all sorts of graphical/boot problems and also a 'machine gun' cracking noise through the speakers.
