Turns out it was the motherboard.
I arrived home from a vacation and ultimately decided to turn on my September 2016 Area-51 R2. But, all power USB and HDMI coming out from the PC doesn't appear to power on, my monitor emptiness my mouse nothing my keyboard extinct. I tried replacing the CMOS battery but to no avail, tried swapping the GPU various times still nothing, tried a CMOS reset and still nothing. The PC itself powers on fine but all the USBs appear not to work whatsoever, I've never had this issue before and it seems to have just stopped working while I was away, and since my warranty has expired (September 2017), I can't contact support but I have sent a renew form. If anyone has had this issue before or has a fix please could you post a fix? Thanks in advance.
Area-51 R2, USBs not working