Windows Explorer My Network Places Refresh

The My Network Places tree does not refresh for very long intervals
(hours or days sometimes).

After I have shut down my laptop (which has been on wireless port to
my wired network), the Laptop shared directories remain displayed in
Windows Explorer for long periods (My Network Places/Entire
Network/Microsof Windows Network/Workgroup/Laptop).

Similarly for those Laptop directories that are listed as direct sub
directory entries off of My Network Places. View/Refresh does not fix
this.

Also, when I again turn on the laptop, it's shared directories do not
appear for some time if they were eventually removed during a long
(hours or days) disconnect period.

How do I force Windows Explorer to update the network tree to match
actual current conditions? As I said, View/Refresh does not work.

Dick Ballard