PC Won't Wake or Boot After Sleep

[exeleon]

Hey everybody,

As I went to head to bed this evening, I noticed the pulsing power LED on my custom built PC indicating to me that it was on and in sleep mode. I walked over jiggled the mouse for a moment and when I saw that it was not responding to the movement I tapped the left mouse button a few times. I glanced back down at the LED on the PC case and noticed the LED come on and then slowly (~7-10 seconds) fade off (not typical behavior). I peaked in through the case window and noticed the light on the motherboard was not on (this is usually always on whether the machine is on or off). I attempted to turn the machine on again via the power button and it was unresponsive. At this point I began to get frantic, I unplugged the power cord from the power supply waited a moment then plugged it back in and hit the power button again - still no lights on the mobo or booting. The only way I can get it to boot, is to pull the CMOS battery, reinsert it, and it boots, goes to bios setup (as if it has forgotten all bios settings), after exiting bios, it works perfectly fine... until the computer sleeps, then it goes unresponsive again and all the mobo lights go dark. I tried replacing the CMOS battery with a new one thinking that was the culprit, but to no avail.
Some other things I've noticed are although the power light on the mobo goes out, the ethernet ports on the back of the machine are lighting up an has any advise I'dd when I can get the machine to start, the mouse cursor movement is rather jerky -  if that info is of any use to anyone out there. I built this machine around 3 years ago and it has never given me any indications of instability, it been extremely reliable up until this point. Here's what's inside:

Mobo: ASUS Z97-A
CPU: Intel Core i7-4790K
GPU: MSI GeForce GTX 970
RAM: G.SKILL Ripjaws X Series 8GB
Power Supply: Rosewill ARC Series 750W
Storage and OS: Windows 10 installed on a 250GB Samsung 850 EVO SSD and theres also an internal Seagate Desktop HDD used for storage.

 The only things plugged in the back of the machine currently are the ethernet cord and that adapter to my logitech wireless keyboard and mouse.
Can anyone out there offer advice on how to troubleshoot/fix this?

Update: I just noticed I can also get it to boot back up by fully unplugging the machine and letting it sit for some time, plugging it back in and hitting the power button. If anyone has any advice out there I'd greatly appreciate it!