it is a processor over heating siren.
Reseat your Heat Sink and change the Thermal Interface Material.
So this just happened as in all was working fine the other day or did you upgrade your CPU or something?
Could be that the fan has died.
Thank you. No more beeps, life is good. Thank you once again
New board and cpu, and unfortunatly a poor job of installing the cpu. Thank you very much for your support.