I need help here. Problem is, my laptop Acer Aspire 4520 cannot switch ON. I use AC Adapter (Checked OK) and when I pressed the Power Button, the power light is ON and then it OFF. I try to changed the RAM slot - unsuccessfull try changed to new RAM - unsuccessful try changed to new Processor - unsuccessfull remove and fitted back CMOS Battery - unsuccessfull Strange is that when I remove all RAM, HD, Processor and switched it ON. The power light on motherboard remian ON. But when I put back all the component one by one, power light is ON and then it OFF. What's happen here? Any suggestion?