Did you try it outside the case? Example follows.
I am new to the forums and hoping for a bit of help/advice. I have a 10 month old computer, which is the 3rd I have build. Until recently it has been running like a champ. I recently began getting restarts randomly, followed by an error message saying Asus MB had detected some sort of voltage error. After randomly happening a few more times I decided to read up and discovered a few threads with similar issues. The most common answer seemed to be to turn off the feature in the bios, which I did. The issue soon reappeared, and after the next attempt to reboot, nothing happens. I can hear the power supply, get power light on MB as well as a flashing amber light on the LAN port, and the DVD drive attempts to run, and I am able to open/close it. Upon further reading, I next tried the CMOS pin, as well as resetting the battery, none of which helped. Out of desperation I bought a new power supply assuming that must be the issue. After installing the new power supply, and attempting to boot the system, I am back to square one. Next step was replacing the MB. Did this, worked for a few hours, then shut down, back to square one. Any suggestions would be very much appreciated. I keep my computer very clean and air dust internally at least once a month. My components as listed below.
Intel Core BX80646I74790K i7-4790K Processor (8M Cache, up to 4.40 GHz)
ASUS Z97-A ATX DDR3 2600 LGA 1150 Motherboards Z97-A
Corsair Vengeance 16GB (2x8GB) DDR3 1600 MHz (PC3 12800) Desktop Memory (CMZ16GX3M2A1600C10)
Asus 24x DVD-RW Serial-ATA Internal OEM Optical Drive DRW-24B1ST (Black)
Seagate 1TB Desktop SSHD SATA 6Gb/s 64MB Cache 3.5-Inch Internal Bare Drive (ST1000DX001)
Cooler Master Hyper 212 EVO - CPU Cooler with 120mm PWM Fan (RR-212E-20PK-R2)
ZOTAC GeForce GTX 980 AMP! Edition 4GB
EVGA SuperNOVA 750 G2 80+ GOLD, 750W ECO Mode Fully Modular NVIDIA SLI and Crossfire Ready 10 Year Warranty Power Supply 220-G2-0750-XR