1.Power up your computer and wait for a short beep.
2.Remove the RAM and the third-party video card (if there is any) and power up your computer.
3.Reset the RAM in other slots if there are any.
4.Try another working RAM if possible.
5.Check if the motherboard speaker is properly attached to its designated slot.
6.Try a different power supply.
7.Remove the motherboard out from the case and place it on an insulated surface.
8.Reset the CMOS.
9.Try inserting your other system hardware components (RAM, CPU, Power Supply) to a similar motherboard.