1) If the motherboard is new, and flashed to F20 at time of manufacturing it is fine.
Otherwise you'd need a CPU compatible with your BIOS. Some motherboards can flash BIOS without a CPU but I'm pretty sure this model doesn't support this.
2) Problem may be the power supply, motherboard, CPU insertion, CPU cooling, memory sticks, cable connection or other.
- fan test doesn't prove PSU absolutely BTW
3) Questions/solutions: (not necessarily in order)
1) unhook all drives
2) remove a graphics card if installed (and use the Intel iGPU)
3) verify connector for power fully inserted to main 24-pin and CPU
4) ensure MEMORY sticks fully inserted
5) can you enter the BIOS?
6) if so, also run MEMTEST86 www.memtest86.com
7) if no, it's a...