My Network Places has CLSID 208d2c60-3aea-1069-a2d7-08002b30309d
Knowing this, you can read the default registry value at HKEY_CLASSES_ROOT\CLSID\{208D2C60-3AEA-1069-A2D7-08002B30309D}\DefaultIcon
The result will be i.e %SystemRoot%\system32\imageres.dll,-25