(that's the red wire connected to motherboard IDE connector pin 1 and HD pin 1).
Uuummm... not always. Some IDE ribbon cables don't have any color coded wires at all. Some that do, don't have the "key" in them so they can only be plugged in one way. In that case you'll be cutting pin 40-something if the cable is connected reversed on both ends. The only way to be truly sure you're cutting the pin 1 connection is to check the motherboard and the drive connectors for the location of that pin.
