[Troubleshooting] PC starts up with no display and no keyboard functionality.

Hi, I posted about this yesterday but havent gotten a fix. I was playing a game when I got up to use the bathroom and upon returning my PC was on but my keyboard, mouse, and monitor were not functional. I have tried some suggestions such as removing the RAM, unplugging the PSU and draining the mobo, unplugging the PSU for a while, etc etc. One thing people have told me to try is removing the CMOS battery from my mobo but it seems that my mobo does not have one. Instead it uses UEFI to work the BIOS although I'm unsure what that means. What would be the equivalent to try unplugging the cmos battery on a mobo that uses UEFI? Also I am having a hard time deciphering what powers what so I cant tell whats the problem. Can someone explain to me things such as for example what would or wouldnt work if the mobo was the problem or what would or wouldnt work if the PSU was the problem etc etc. Thanks. Here is my parts list:PCPartPicker part list / Price breakdown by merchant Type Item Price CPU Intel Core i5-4690K 3.5GHz Quad-Core Processor $224.95 @ OutletPC CPU Cooler Corsair H100i 77.0 CFM Liquid CPU Cooler $168.99 @ Amazon Motherboard MSI Z97-G55 SLI ATX LGA1150 Motherboard - Memory G.Skill Sniper Series 8GB (2 x 4GB) DDR3-1866 Memory $44.99 @ Newegg Memory G.Skill Sniper Series 8GB (2 x 4GB) DDR3-1866 Memory $44.99 @ Newegg Storage Crucial MX100 256GB 2.5" Solid State Drive $109.00 @ B&H Storage Hitachi Deskstar 7K2000 2TB 3.5" 7200RPM Internal Hard Drive $64.80 @ Amazon Video Card MSI GeForce GTX 970 4GB Twin Frozr V Video Card $309.99 @ Newegg Case Corsair 650D ATX Mid Tower Case - Power Supply EVGA 750W 80+ Bronze Certified Semi-Modular ATX Power Supply $59.99 @ NCIX US Optical Drive Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer $17.78 @ OutletPC Operating System Microsoft Windows 8.1 (32/64-bit) $108.98 @ OutletPC Prices include shipping, taxes, rebates, and discounts Total (before mail-in rebates) $1204.46 Mail-in rebates -$50.00 Total $1154.46 Generated by PCPartPicker 2016-02-20 18:08 EST-0500