Download Old Versions of Internet Explorer
Windows automatically downloads and installs operating system upgrades at the click of a button. Because Internet Explorer is a part of the OS, your browser gets upgraded too.
That's a good thing right? Always having the latest and greatest versions of everything! So why would you want to have old, grungy versions of IE lying around?
Here are some reasons:
A) Some websites work better in older versions
OK, really, if you're accessing a site that works better in IE6 than IE7, there are some serious problems. E-mail that webmaster!
B) Usability Testing
With each upgrade, Internet Explorer has been improved upon. But this also means changes have taken place in browser functionality. We know that some people are still using as old a version as IE5, so it's necessary to test programming in those browsers.
C) Design Testing
This works in tandem with usability testing. Each browser treats CSS a little bit differently, and IE varies the most between versions in its rendering of web pages. In order to make sure you've coded your new design correctly, you need to check it in as many browsers as possible.
Now that you've been convinced, how do you go about getting older versions of IE onto one computer? The older browsers aren't on your computer anymore thanks to the upgrades, and if you try to roll back, you'll lose the newer versions.
Here's one way: In 2003, a couple of programmers made it possible to install and run Internet Explorer as a standalone program, without overwriting any other versions. Yousif Al Saif created a package installer which allows you to download IE3, IE4.01, IE5, IE5.5, and IE6. Select which versions you want, and the program creates handy shortcuts for you. This installer is meant for use on Windows XP machines.
Another method: Evolt is a community of webdevelopers that host archives of browser versions online, where you can download the version(s) you want for free.
As always, keep in mind the dangers of using older software, especially of the online variety. Bugs and security holes can leave your operating system vulnerable, so make sure you have a firewall enabled and run your anti-virus software regularly.