"The computer Whisperer"

Problem: Folders sometimes do not open in a new window when that mode is selected. (Vista)

Open Windows Explorer
by clicking on The Vista Pearl "Start" then "Computer"
The Computer Window opens depending on your settings. Here there is the Navigation pane on the left and the and the preview pane on the right.
Notice that with the folders visible in the Navigation (left) pane "Explore" is the default action for a double click.
Clicking on the down chevron above removes the folders from the navigation and makes the Open function the default action for the double click.
You must also be sure that you have set the proper folder options in order for  the open command to Open in a new window.

If the toolbar is not showing hit the ALT key to make it show up then select tools, or just ALT + T.  Then select Folder Options.
In the Folder Options window, Browse folders section, make sure that the radio button beside "Open each folder in it's own window" is selected.
Then with no folders showing in the Computer window click on drive C:\ and it will open in it's own window.  
In addition, if the Navigation pane is not present Open will always be the default and "Open in New Window" will always work. To remove the navigation pane drop down the "Organize" list select layout and click on the blued Navigation pane to turn it off.
This will cause a single pane window and Open will be the default action.