I got my new laptop recently and after I did the Windows Update, IE 9 appeared in my laptop. I wanted to keep IE 9, but I couldn't because our projects need to use IE 8 all the time. It is easy to uninstall IE 9 and roll back to IE 8.
Go to Programs and Features.
Click View installed updates.
Right click Windows Internet Explorer 9 and you can uninstall it.
After rebooting machine, IE 8 is back.
If you would like to test web pages on multiple Internet Explorer versions at the same time, IETester is a good tool.