Simplify. Disconnect everything but one stick of ram, and your OS drive. Reset BIOS to default. You may even just connect your monitor to see the bios through your video card and not have your OS drive installed.
Check to see if your computer will boot. If not, try the ram stick in another slot. Still no boot, try a different ram stick in the first slot. It takes patience and keeping track of what you did just so you don't start doing the same thing over and over again. It is possible you had a hardware failure. I once had a board that failed to boot and it turned out an overclock on my RAM was the reason. I had forgotten I had overclocked it. It has been working for months with the overclock. Once the ram was set to board default (not the XMP setting of the ram), the board booted.