In Windows 7, opening a second instance of something, like the Documents Library or Internet Explorer got a lot harder. If you already have one instance of something open and click your shortcut on the Taskbar, a new window will not open. For the first few weeks after I switched, the only way I knew to open a second window was to right-click on the shortcut on the Taskbar, and select the name of the thing I wanted to open. Then a co-worker introduced me to a fantastic keyboard shortcut.

Here’s the secret:
Hold down the Shift key while you click on the Taskbar shortcut, and a new window will open.