Upgrading Home Prem. to Business

I have a Home Prem. desktop that I want to upgrade to Vista Business, but when I put in the product key it would did work.

Do I have to use the install DVD to upgrade it to Business?

As far as I know, even though a particular DVD generall includes all the different Vista versions, I don't believe that you can upgrade simply by providing a different key -- but I have not tried this.

In general, you upgrade by inserting (or downloading) something known as the Anytime Upgrade -- and providing the special upgrade key that came with the purchase. If you purchased the upgrade online from Microsoft, they sent you an email containing the upgrade key.

Also, I don't believe that you can do an in-place upgrade from Home to Business. I believe that you will have to do a re-install.