One beep code table I found say for Award BIOS (which your board has), 1 long + 2 short beeps "Indicates a video error has occurred and the BIOS cannot initialize the video screen to display any additional information".
Check your manual, pages 33 and 66-72 for how to read 2-digit error codes on the mobo debug LED readout.
One thing to check: see manual p 52, configuring the initial video display. You must set here in the BIOS whether your video card in is a PCI or in a PCIEx slot. they are not the same - set it wrong and the BIOS cannot find your card.