This problem has been very intermittant for the past 2 months. It's only occured a few times though. Not sure what you mean by POST? When I press the power button on the computer, the ( Amber light on the monitor) goes on but there is nothing but a dark screen.
This is an emachines T6420 with Athlon 64 3400+
I have removed the Ram and turned it on with no change, fans still racing.