Computer shut off randomly, LEDs and fans turn on for a second then shut off and won't start.

So yesterday I put in a new video card and power supply after getting them for christmas, everything was working fine until around 3:30am last night when my PC shut off and wouldn't start again, only the lights and fans would turn on briefly then shut off, and they wouldn't do it again unless I switched the power supply on and off. I took out my new video card and it wouldn't start, I put my new card back in and switched my power supply for the old one. It stuttered a few times but it turned on and stayed on, to confirm it was the power supply I put the new one back in and went to turn on the machine and it turned on just fine and stayed on all night. I figured it was an overheating issue because the GTX 970's with ACX 2.0 have a feature where the fans won't turn on until it reaches 60º C. I changed the fan curve for the fans to run at lower powers at lower temperatures and then kick in to higher speeds when the card gets above 50º C, I also ran a FurMark test on the GTX 970 it got up to 75º C and stayed there for 2 minutes with no problems. I thought I had the issue solved because my computer stayed on all night (left it on to see if it would shut down again) and completed the scheduled backup. I was on my computer all day today and it worked fine, I even heard the GTX 970's fans kick into gear while playing a heavily modded Skyrim. I was surfing the internet when around 3:30am, the same time as the night before, my computer shut off and started doing the light up for a second and shut off thing again. I checked to make sure all the connections were secure, they were, I unplugged one video card it wouldn't start, I unplugged the other one and it still wouldn't start. I could see the SLI LEDs were on so I thought maybe having SLI enabled while not actually having the cards SLI'd could be causing the issue (I had tried to SLI my cards before realizing you can't SLI a GTX 970 with a GTX 760) I turned SLI off and my computer still wouldn't start. When I have the power supply switched on I can see LEDs on my MoBo so I know it's getting power but my computer won't start. I read something about the computer being stuck in standby mode which I thought might be my problem since it shut off the same time it did last night but I don't know how to tell. I guess it's worth mentioning that I've been having an issue lately where when I slept my computer it would randomly come out of sleep mode. Also I tried using DifferentSLI before I realized that the cards simply weren't compatible so my windows is currently in test mode, could that be the issue? I'm going to go to bed and I'll swap the power supplies once again tomorrow just to make sure it isn't a PSU issue, hopefully between then and now someone can give me an answer as to whats wrong with my machine. Thanks in advance.

My machine is about 1.5 years old
Specs:
ASUS X99 Deluxe
EVGA SC GTX 970 ACX 2.0
EVGA SC GTX 760 FTW
SoundBlaster Z
Intel i7 (I seriously can't remember which processor I have right now sorry, I think it's either a 4790K or a 5930K but I remember it was $500 in October of 2014)
Corsair 850M

Update: Well I was able to uninstall DifferentSLI, I also did a clean install of the Nvidia drivers, computer seems to be running fine. I'll update this again if it shuts down again at the time it did the first two nights.