Internet Explorer 7 (IE), released in October 2006, greatly improves its CSS rendering capabilities. However, it's only available for Windows XP and Vista, so we still have to support IE 6 — and possibly IE 5.5 and 5.0, depending on your site's audience — for some time to come. Unfortunately, the integration of IE into the Windows operating system, and Microsoft's refusal to allow multiple versions of it to run at the same time, have made testing web sites in various versions of this prevalent browser difficult. There are, however, ways it can be done, and the advent of IE 7 has brought some new methods out for our consideration. In this article I'll provide an overview of the current options available for testing multiple versions of Windows IE, and provide the pros and cons of each method so you can decide which suits you best.