The blinking amber light indicates that it is receiving electrical power, but an internal power problem might exist. Could be a motherboard.
See your troubleshooting guide here:
I am using a dell XPS 720 computer with a 750 watt N750P-00 power supply whenever i plug in the power supply it will just start making a loud repeated clicking noise, the light to the power button on the front of the computer flashes and the light on the motherboard stays on. hitting the powerbutton does nothing, i have tried all forms of connections to it and it only happens when the power supply is plugged into the motherboard, i ordered a new power supply which arrived today but it did the exact same thing when i plugged it in. I am not sure if its then the motherboard with the problem or i was sold a bad powersupply. Any help would be appreciated