Beeping system

I just built a new system, here are the specs. Asus k7m-rm MoBo, Athlon 500 CPU, 16 meg riva tnt video, yamaha built in sound, 13 gig maxtor ata66 HDD, 128 meg pc100 sdram, 6x pioneer dvd, 4x4x32 acer cdrw, external pheobe 56k modem soon to be changed to zoom dualmode 56k, altec lansing speakers. The thing is it constantly beeps. as soon as I turn it on it starts and never stops, but the system works great. I use it every day but the beeping is driving me nuts. I have tried disabling on board sound and that did not work. by the way the beeping seems to be coming from the internal speaker, not the external ones. I don’t understand it but any help would be appreciated. thanks.