Symptoms: Machine was running a music cd when it went silent and the monitor screen went black. No response to the keyboard or mouse. A hold on the on button produced a reboot that only started the fan and then within 3 seconds produced a tone (boooooooooop) which lasted about 3 to 5 sec. and then a silent period of about the same duration, followed by another cycle of this which continues until madness is produced in all persons in the room ...or on the phone.
What is the most likely cause? That is, what failed and what might be damaged?