In fact, 我想知你條USB cable 會有2個頭定1個頭?照你所講, 有可能你條USB cable 有2個頭而你用左最未端o個個. 因為未端o個個頭係for唔夠電時用的 (some old computer is using USB v1.1, but now most of computer is using v2.0).
One of question, your computer is old?? or can you know your computer USB is using v1.1? otherwise you may connect 2 USB in your computer.