Function NextButtonClick(CurPageID: Integer): Boolean;
Begin
Result:= True;
if (CurPageID = wpSelectDir) and (Pos(Uppercase(ExpandConstant('{pf}')), Uppercase(ExpandConstant('{app}'))) > 0) then Result:=MessageBox(StrToInt(ExpandConstant('{wizardhwnd}')), 'Вопрос', 'Установка в Program Files', MB_YESNO or $30) = idYes;
End;