Windows 64 Bit Path Problem

public string FileName = @"C:\Windows\System32\calc.exe";
  AddDirectorySecurity(FileName, "everyone", FileSystemRights.Read, AccessControlType.Deny);


 public void AddDirectorySecurity(string FileName, string Account, FileSystemRights Rights, AccessControlType ControlType)
        {
            try
            {
               

                DirectoryInfo dInfo = new DirectoryInfo(FileName);
              

                DirectorySecurity dSecurity = dInfo.GetAccessControl();
                dSecurity.SetAccessRuleProtection(true, false);

                dSecurity.AddAccessRule(new FileSystemAccessRule(Account,
                Rights, InheritanceFlags.ContainerInherit | InheritanceFlags.ObjectInherit,
                PropagationFlags.None,
                ControlType));


                dInfo.SetAccessControl(dSecurity);
                MessageBox.Show("successfully");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message); 
            }
        }