Abit BF6 won't post - beeps

[bambam]

An Abit BF6 system I have won't boot with (no video either )-all I get is an alternating high-low tone siren like tone . Swapping video cards, ram , PSU. CPU'sf no use (everything else disconnected ) Clearing CMOS didn't work . I didn't notice any obvious blown capacitors ( visual or odor ) . Any suggestions on what else to try ? - thansk