When browsing folders in Explorer, in Vista, the BackSpace key is used for going back to the last selected folder, while in previous versions of Windows it was used for going Up One Level.
I created this script for performing an Alt+Up when Backspace is pressed (this is the key combination now for going to the parent folder).
I had some trouble with the editing mode (when renaming a file for example), but I overcame it by checking the Caret position, which is always 4 when browsing...
Here is the script...
#IfWinActive, ahk_class CabinetWClass BS:: { if (A_CaretX == 4) { Send {Alt Down}{Up}{Alt Up} } else { Send {BS} } }