How old is that board? You might need to update the BIOS for it to work with that gfx card.
You need to look up the beep codes for that specific board. Cos it might be a hardware problem, as in either the card is not getting power or the slot is dead and the bios can't properly boot it.
Before you do anything, tripple check the gfx card is properly inserted. Take it off, put it back on, plug the power cables to it and try again. Sometimes the simplest answers are the best solutions.