Have you installed the EOS Utility BEFORE you connected your camera to you computer?
If you did not, then it's your own fault. With USB devices, ALWAYS install software first, then connect devices.
When you connected your camera to your computer before you actually installed the software, Windows could not find a driver and probably marked your camera as Unknown Device in the Windows Device manager.
Google a bit to find out how to remove the Unknown Devices from the Device Manager, if applicable...
Also, you didn't actually try to connect your camera to a USB 1.1 port did you? Only USB2.0 and upwards is supported. See the system requirements of the utility for that.