USB header / cable

I need to add a couple USB ports to an older computer (PC-Chips M787CLR mobo), and it has a USB header on it. This USB header has 10 pins. I have an extra 2-port USB cable from my current case (it came in the front panel), and I hacked up an old parallel port slot cover, and put these USB ports in place of the parallel port. I was just going to put it in, when I saw that the header on the motherboard has 10 pins. This cable has 9 pins, one of the corners is 'keyed' and has no hole for a pin to go in. So I can't plug this in. Is it safe to just break off the pin on the motherboard that is extra?

I would guess that you could do this but you would have to look at the MB manual and the pin diagram for the header to make sure that you have the VCC pins lined up. I would not do it unless I first saw the pinouts.

Note: the VCC should be the red wire.

get yourself a needle, and make it hot, and stick it through the blanked spot on the plug, trying to keep it centered, or you might be able to push it through vrom the back and pop out the cover without it being hot. then after you make the blank spot a hole, it should go on relatively easily.