Visit https://addons.mozilla.org to download the IE NetRenderer Firefox Extension.
In the search box search for IE NetRenderer and click on the green button to search.
Now the search results should display IE NetRenderer, if it does click on the green Add to Firefox button to install the Extension.
Now click on Install Now
IE NetRenderer will now be installed. After installation click on Restart Firefox so that you may use the IE NetRenderer Extension and that the installation may be completed.
Right click on the web site you are currently viewing and hover over Render in… and a new menu will appear. Now click on the Internet Explorer version in which you would like to render the web page. A new window will appear with a screenshot of how the page will look in the selected Internet Explorer