In this post I'd like to give you some information where to locate old software. You wonder, why do I need to look for an old programs ?
The answer is you need to run the old version for some reason. For example the newer program is not really better than the previous one, or there are so many issues that you prefer to use the old version instead of upgrading to the latest version.
Other examples could be in case you are a programmer and you need to test a program with other application in many different versions , for example, Java Runtime Environment 18.104.22.168, 22.214.171.124, etc. or Microsoft Internet Explorer 5.5, 6.0...
The main problem could be locating the different program versions, usually on the website of the majority of software companies you find easily only the current version. For this reason is better to look in other directions. There are some websites where you can download the old version of popular applications.
[Link added, thanks to TomskiBOTN]
About software evaluation see also these posts :