Fix for Vista Help not working after installing Dreamweaver
If you install Dreamweaver 8 (or the 8.01 or 8.02 updater) on a computer running Microsoft Windows Vista, Vista's Help system may stop working. Whenever you click on a Help topic, the request will fail and you will see the message "Internet Explorer cannot download / from help." This is caused by the Dreamweaver installation modifying a particular registry key that Vista Help relies on. (Specifically, under HKEY_CLASSES_ROOT\.xml the value "Content Type" must be set to "text/xml" for Vista Help to work.) You can set this value back to Vista's original setting by downloading the following Zip file, double-clicking on it to extract the enclosed file, and then double-clicking on that file to do the reset. Vista Help should then function correctly. We are not aware of this reset having any adverse effect on Dreamweaver.
This problem identification and fix was based on a Web page published by Kristan Kenney.