DISCLAIMER: Please make sure to first turn off and keep your power supply unplugged.
You do not need to connect the AvalonMiner to any computer motherboard. Instead, the trick that miners use is to cut a paperclip and fold into a “U” shape. Then, insert one end into the green wire and the other end into either black wire on the normal motherboard connector cable. Use electrical tape to tape up the connection safely.
Then, the power supply on and off switch controls the power on or off for your power supply.