This is a little strange.
I believe that the adapter you have is the one that comes with a short extension lead - are you plugging the extension lead in with the adaptor or are you plugging the adapter straight into the laptop I would plug it straight into the laptop to begin with.
When you plugged the adapter in did you get a message saying that a new device had been recognised?
I would be inclined to delete the installation and start again - making sure that the adapter is plugged directly in a usb port - try a different one this time. If this fails then try to download the driver from the site I have given below.
You should be able to download the driver you need from here - from the information you have given me I think it should be the first one but plese check.