Microsoft Windows XP - Connect Two Computers With A USB Cable, But Beware
You can connect two computers via a USB cable in order to share files, but you can't use standard USB cables. Warning: If you use a standard USB cable, you might damage the USB ports on both systems, or even the respective system boards.
Instead, you need to use a special USB cable, known as a USB Bridge cable. A USB Bridge cable reverses both the send and receive signals as well as the power voltage, so that you don't create a short.