I had to reset it manually by pressing the small button on the rear once, I can only assume this reset the firmware to the factory setting, but before this it showed all ports closed.
I have tried both manual and automatic update, and can download the correct files but after it has gone through the motions it still says update available so obviously doesn't take.
I know that each computer behind it has all ports stealthed so any scan ends at the router, and it shows some ports open.
Also at the set up page Unplug and play keeps being enabled even after I set it to be disabled. Possibly a virus infection on a computer telling it what to do?