It need not be your hdd only that is the cause of the problem. If you are getting any beeps from your system(if your system speaker is up) while boot up then it means either your ram needs to be readjusted (plug it out and then in again). If you have a graphics card then check that one too, 'cos it too creates problem of that sort although the beep count is different. The main reason why I don't suspect a prob with your hdd is that the display itself doesn't come up .. now if your hdd was the problem, the display shoudn't be affected!!!!