Explorer.exe switches (taken from http://support.microsoft.com/support/kb/articles/Q130/5/10.ASP)
EXPLORER.EXE [/n][/e][,/root, ][[,/select],]
/n: Opens a new window in single-paned (My Computer) view for each item selected, even if the new window duplicates a window that is already open.
/e: Uses Windows Explorer view. Windows Explorer view is most similar to File Manager in Windows version 3.x. Note that the default view is Open view.
/root, : Specifies the root level of the specified view. The default is to use the normal namespace root (the desktop). Whatever is specified is the root for the display.
/select,: Specifies the folder to receive the initial focus. If "/select" is used, the parent folder is opened and the specified object is selected.