You may have installed the ribbon cable to the ATA hard drive backwards. Anytime you get three beeps instead of just a single peep, you have a problem. Sometimes connecting the cable backwards can fry the CPU or MOBO.
The ribbon cable on HD must be installed with the red tracer facing toward the four power input pins. That is not a hot-swap cable. The system must be turned off when the ribbon cable is either unplugged of plugged in.