procedure InstMSI;
var
  vysl: Integer;
  param : string;
begin
  param := ExpandConstant('/quiet /uninstall "{app}\vOKOsComsetup-ch.msi"');
  Exec('msiexec', param,'', SW_SHOWNORMAL, ewWaitUntilTerminated, vysl);

  if IsWin64 then
    begin
      param := ExpandConstant('/quiet /i "{app}\vOKOsComSetup_x64.msi"');
      Exec('msiexec', param,'', SW_SHOWNORMAL, ewWaitUntilTerminated, vysl);
    end
  else
    begin
      param := ExpandConstant('/quiet /i "{app}\vOKOsComSetup_x86.msi"');
      Exec('msiexec', param,'', SW_SHOWNORMAL, ewWaitUntilTerminated, vysl);
    end;
end;
