Magst du die Registry? Was steht dort unter HKEY_CLASSES_ROOT\Folder\shell ?
Fallst dort ein Eintrag "explore" fehlt, speicher das nächste als Text mit Endung .reg und versuch einen Doppelklick.

Code
Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\Folder\shell\explore]
"BrowserFlags"=dword:00000022
"ExplorerFlags"=dword:00000021

[HKEY_CLASSES_ROOT\Folder\shell\explore\command]
@=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,6f,00,74,00,25,\
  00,5c,00,45,00,78,00,70,00,6c,00,6f,00,72,00,65,00,72,00,2e,00,65,00,78,00,\
  65,00,20,00,2f,00,65,00,2c,00,2f,00,69,00,64,00,6c,00,69,00,73,00,74,00,2c,\
  00,25,00,49,00,2c,00,25,00,4c,00,00,00

[HKEY_CLASSES_ROOT\Folder\shell\explore\ddeexec]
@="[ExploreFolder(\"%l\", %I, %S)]"
"NoActivateHandler"=""

[HKEY_CLASSES_ROOT\Folder\shell\explore\ddeexec\application]
@="Folders"

[HKEY_CLASSES_ROOT\Folder\shell\explore\ddeexec\ifexec]
@="[]"

[HKEY_CLASSES_ROOT\Folder\shell\explore\ddeexec\topic]
@="AppProperties"