If the BIOS is slow to respond it can indicate CPU/Northbridge/Southbridge overheating (poor heatsink contact) or corrupt BIOS settings or another piece of hardware may be faulty. What graphics card(s) have you installed? Newer models such as GTX 10x0 series may cause problems. 1. Check CPU, Northbridge and Southbridge temperature under hardware monitoring, what temps are they? 2. Clear CMOS on the motherboard and take the battery out and leave the motherboard unplugged from the power supply (to allow the capacitors to discharge) then check if BIOS is still slow. 3. Strip the board down to minimal hardware e.g. CPU, graphics card & 1 stick of RAM, make sure to remove all hard drives, optical drives (CD/DVD) and floppy drive then retest. If all of that fails you may have a faulty CPU, PSU or motherboard. I would try another power supply if you have one spare. As a last resort you could try to flash the motherboard BIOS but it may fail and brick the motherboard if the motherboard is not operating properly - try at your own risk!