Kill power to USB port or ports

Hi

I have Googled this and not come up with any real answer, I am hoping someone here may know if it is possible to kill the 5v power on a USB port or even on every port from within an Autoit script? I am running Windows 7 Home Premium. The reason I need to know is I am powering a PCB from the 5v supply of a USB port, I can send the data through the USB port to soft reset my PCB but I would like to do an actual power cycle to 100% ensure all the chips get reset.

Thanks in advance.