[JMS40]

Here's how I do it.
In Local Area Connection Properties, (Control Panel > Network Connections > right click on your Local Area Connection and choose Properties) select " Show icon in notification area when connected". That puts an icon on your start bar always visible when the net is enabled you can use as a quick disconnect.
Just right click and "disable".

To make re-connecting easy, make a shortcut to Network Connections for your desktop or quick start bar. Click on it, double click the disabled Local Area connection and it's enabled and you're back online.