If it's a port on the top/front/side of the case, you find that a lot of pc builders don't bother connecting those ports to the motherboard headers.
Try using one of the ports on the back of the case, the ones that are built into the motherboard.
Like you suggested, they could also be disabled in the bios, the drivers might not be installed, or there could be something wrong with the USB memory stick.
If the port works for mice etc, then it works. The problem is probably the memory stick. Not that it's broken, necessarily, it could just be unformatted.
Try:
right click my computer
manage
storage
disk management
In the bottom right pane, is your USB drive there? If so, the PC's recognising it, it just isn't formatted in a way that windows can read it.
Gary, November 2010
