If you want to run Windows Vista on your computer without disturbing the existing setup, the best option for you is to download a free copy of Virtual PC and install the associated Vista virtual image*.

Now if that sounds a bit complex, here’s something more simple for you that requires no downloads or complex setup.

Called the "Windows Vista SPI Ultimate Test Drive", this product
from TechNet Virtual Labs let you test Windows Vista online inside a
browser without making any changes to your current work environment.

To experience it live, just go to windowsvistatestdrive.com.
You get a chance to explore all features / programs included in Windows
Vista (including games) and also Microsoft Office Profession 2007 as
you may noticed in the screenshot.

You can explore Vista on your own, or follow along with guided exercises and videos. There’s something similar for Office 2007 if you like to try out just Microsoft Office 2007 in a browser without Vista.