I have the ASUS SABERTOOTH Z77 LGA 1155 Intel Z77 if the power supply is outputting anything the power good led on the bottom of the mb should be on. it a green led on the bottom of the mb. also there a led to check your vidoe card if you have one if there a fault the led will be red and a ram led. if none of these led are on check that you used the case standoffs and did not short the mb out to the case. for the power supply if you have to take it out of the case and use the green wire trick to see if the power supply turns on.24 Pin ATX 4 Pin ATX
To perform the PSU Paper Clip test, we’ll need to examine the power supply connectors closely and find the one that has a lone green wire. Ninety nine percent of the time, this green wire is located on pin 14 on the bigger connector. In addition to the green wire, locate the other black wires that are present in the connector.
Once the wires are located, you will need a paper clip.
Green & Black Wires + Paper Clip
It is now time for the fun part. First you need to reshape the paper clip into a shape that is similar to the letter C.
Once this is done, make sure that the power cord is NOT connected to the power supply then connect one end of the paper clip to the green wire and the other end to one of the black wires present on the connector.
& Black Wires + Paper Clip
Once the paper clip has been attached to the green and black wires, this will enable the power supply to turn on while it is disconnected from the motherboard something not possible, otherwise. After this is done, turn off the power switch, if one is present, and connect the power cord to the PSU.
Cord Connected
If the PSU does not have a switch, then as soon as you connect the power cord, power should flow through the PSU and you can then observe the fan on that power supply to see if it turns.