Hi. My MacBook ha just developed a problem where it freezes then 'dies'. It's been doing it for a few days now and happens often, under light use. Once off it beeps slowly and loudly in quite an alarming way, until I press the power button. A few months ago I did some upgrades on the ram, changed the HDD to solid state and changed the optical drive for a 2nd HDD. The system was working amazingly well until a few days ago. Does anyone know where / how to start looking for the source of the problem?