that mobo does not exist. did you mean a z68 or z77?
Either one is going to have UEFI
Look in your motherboard manual for specific details. Between the watch battery and the front panel IO there should be 2 bare metal pegs which say "CLR_CMOS" (clear CMOS). Unplug your system from the wall and short these pegs together with a screwdriver or other metal object for ~20 seconds (if you have good hearing then you ought to be able to hear a high pitch whine as it discharges). After you are done then make sure that nothing touches these pegs together as it can cause issues (ie. make sure that there is not a jumper between them). This should reset everything to factory defaults and get you going in the right direction so that your system can at least POST (initialize).
If that does not work then it is time to try bread boarding your system:
This means taking everything out of your case and hooking up bare essentials on a table (making sure that your mobo is on an electrostatic bag or the packing foam pad it came with). Start out with only the monitor, mobo, 1 stick of ram, PSU and CPU. Short out the power switch header and see if it turns on (screwdriver is the tool of choice here).
If it works then turn it off, add the rest of your ram, and try again
If that works then add things like keyboard and mouse
Next add drives (HDDs, SSDs, and optical)
Lastly add the GPU
If everything works while out on the table, then it is time to take it all apart and build it in your box. More likely than not you will find that you accidentally had something hooked up wrong, or a rogue case screw shorting something out, but you may also find bad parts that need RMA.