Board won't boot

[Sail_Dive_Fly]

I purchased a new 970A-DS3.  Booted up with legacy BIOS fine.  Then I tried to switch to UEFI.  CLEARLY, I did not know what I was doing.
It locked up, would not boot.  I cleared CMOS, reset to legacy.  Upon next attempt to reboot, I hear a long beep, then 3 short beeps, no splash screen, no boot. nothing!  What next?

[absic]

Hi there,

usually 1 long beep followed by 3 short beeps would indicate a keyboard error.