For clearing CMOS, unplug from mains, then remove and replace the CMOS battery. You can even shortcut the battery cradle poles, but usually it isn't necessary. Oh, and there is a clear switch in right lower corner, called CLRTC. Read the
manual page 1-26.
Other: Take off and reseat all memory modules and GPU. Check that all fans rotate at startup. Replug all wires.
If you still aren't up and running, leave only one memory module in place, unplug all drives and reboot. Even without a boot volume you should be able to get a POST message and go into CMOS settings. If no success, try with another memory module, preferably in another slot.
After testing all memory modules in vain, remove all of them, as well as the GPU, leaving only the CPU in place. Reboot. You should hear beeps (check you have a speaker connected like on page 1-36, your mobe doesn't seem to have a beeper installed) indicating missing memory and GPU.
If possible, try to boot with another PSU. Even an older one will do for POST testing.
If possible, test your memory modules and GPU in another computer at least for booting. If they work, then the problem lies either in your CPU or motherboard. If you can get a suitable CPU, try it. If that fails, it's the mobo.
Remember to ground yourself and switch the mains off when playing with components. Good luck!