Keyboard Shortcuts For Use in Dialog Boxes on Windows Vista

You can use these keyboard shortcuts when you open a dialog box.

List of Keyboard Shortcuts for use in dialog boxes:

Keyboard Shortcuts	Functions
Arrow keys	Select a button if the active option is a group of option buttons.
ALT+underlined letter	Perform the command (or select the option) that goes with that letter.
BACKSPACE	Open a folder one level up if a folder is selected in the Save As or Open dialog box.
CTRL+TAB	Move forward through tabs.
CTRL+SHIFT+TAB	Move back through tabs.
ENTER	Replaces clicking the mouse for many selected commands.
F1	Display Help.
F4	Display the items in the active list.
SPACEBAR	Select or clear the check box if the active option is a check box.
SHIFT+TAB	Move back through options.
TAB	Move forward through options.

Source: Windows Vista Documentation