I have a USB port problem. The story is as follows. I had an external hard disk plugged into one of my USB ports. I wanted to remove it, so I closed all the files and then went to "safely remove hardware". It said, for reasons I don't understand, that the device was still in use. I didn't feel like doing a reboot, so instead, perhaps rashly, I just unplugged the external hard disk. Now I am having problems with the port. I tried shutting off the machine and then turning it on again, but this did not help. FYI, the OS I am running is Vista Business. How can I fix this?