object.RootFolder 

function GetRootFolder(drv)
{
   var fso,d;
   fso = new ActiveXObject("Scripting.FileSystemObject");
   if (fso.DriveExists(drv))
      {
         d = fso.GetDrive(drv);
         return(d.RootFolder);
      }
   else
      return(false);
}

Function ShowRootFolder(drvspec)
   Dim fso, f
   Set fso = CreateObject("Scripting.FileSystemObject")
   Set f = fso.GetDrive(drvspec)
   ShowRootFolder = f.RootFolder
End Function