I've had an emachine 270 for about 5 years without problem, but a couple of days ago it would not power down completely. Kept pulsating inside with the sound of fan/drive still running, so had to turn off at mains, now it wont power up again. If the power cable is taken out and plugged in, the case fan only spins for a second and stops, no lights, no drive turning, no sounds, no nothing. Pls, can anyone help. I just want to know if it is the mobo or psu that is gone, so I know what parts I would be getting.