This is some information I had, and copied for you. Most is not of interest, but as the machine was moved, maybe the lose boards is significant.
Also, I had exactly that problem, and the keyboard and mouse PS/2 connectors were incorrectly marked. Changing these around solved the problem.
Beep CodeExplanation and possible solution
No BeepsSeveral things could cause. .your motherboard to remain silent: No power. Did you connect the power supply to the motherboard? Is the power cord plugged into the power supply and the wall? Is the input voltage selector set to the proper voltage for your area (110 or 220 volts). The motherboard isn't installed correctly in the case and it's shorting out. Check for proper installation. No speaker on the motherboard or no speaker plugged into the motherboard. A cable (floppy, hard drive, etc) plugged in backwards. Remember: Pin one on the cable is on the same side as the red stripe, pin one on the device is on the same side as the power connector on the device. Check all cables. An ISA, PCI, or AGP bus card not seated properly in a motherboard socket. Try reseated the cards. A bad clock generator on the motherboard (replace the motherboard).
Good Luck.