Arduino will not load on device manager

I'm a newbie, just bought Arduino Uno, after download will not show up on Device Manager Port (COM & LPT)?
Have Windows 7 on a laptop Acre. Any help would be nice. Thanks

Does it appear in unknown devices? Can you then update the driver? See: http://arduino.cc/en/Guide/Windows and

after download? I don't think it'll show up unless you plug it in.