I did this first: http://news.softpedia.com/news/Disable-Driver-Signing-in-x64-Windows-Vista-53491.shtml I also ran libusb's isntaller as an administrator in XP SP2 compatibilty mode. libusb did not work. I tried restarting and after that all my usb ports did not work. I have the C++ Runtime so that should not be a problem either. It works just fine on my computer with Vista x86 on it. Any ideas as to why this is happening to me?