One question that I get all the time is how to test a website in both IE6 and IE7 on the same computer. Here are some options:
Because the code for Internet Explorer is so tightly integrated into Windows, the only way to run the “pure / authentic” version of IE6 on the same machine as IE7 is by using a Virtual Machine. Microsoft has made this easy by providing a Virtual PC image for this purpose. Virtual PC is also available for free download, so this is a great option. There are two downsides to this option, the VPC image is over 400MB in size, and the image periodically expires requiring a new download every 6 months or so.
The Evolt Browser Archive includes a standalone version of IE6. Simply download the zip archive, unzip and run iexplore.exe. Simplifiy your life by creating a shortcut in your start menu or on your desktop. This is my preferred method, mostly due to the simplicity, and has worked very well for me.
Want to test more than just IE6? Multiple IE installs IE3 - IE6 standalone versions. It’s been a long time since I’ve cared about how something looked in anything earlier than IE6, but if you have a reason to test a site on an earlier version of IE, this is a good way to go.
The above options assume that you’ve already installed IE7. The makers of Multiple IE also have an installer for IE7 standalone (but it’s not integrated into Multiple IE). The idea here is that ou would run IE6 natively, with IE7 in standalone mode. I’ve never sucessfully used this option, but others have found it useful.
Running a standalone version of Internet Explorer is not the same as running the native, built-into-windows version.
Due to IE’s reliance on DLLs and registrty settings, things can get messy in certain situations. Take a look at Taming Your Multiple IE Standalones for more information on these possible snags. In short, they recommend using Multiple IE, as the registry hacks and DLLs are all included.