I find myself constantly fighting the microsoft battle of making things work in their browsers (thanks guys).
On one of my machines I have Vista installed and needed to test a newly created site that apparently had some issues under Internet Explorer 6.
HOWEVER, to my horror IE6 was unable to run on Vista. Once again, thanks Microsoft for making life difficult for everyone out there!
After much grief, pain and agony with a million attempts to get it to run I stumbled upon a really great tool called IETester made by DebugBar.
Take a look at their site.