While searching for how to check Internet Explorer 5.5 / 6.0 and so on in Windows 7, I came across this invaluable little tool called IETester.
This application allows you to test a website on IE 5.5, IE 6.0, IE 7.0, IE 8.0 as well as whatever version you currently have installed all from within the application.
Here’s a test showing Google with each version of Internet Explorer on a separate tab with the IE 5.5 tab selected.
This will certainly save a lot of hassle.