csharp or vba check box

I'm new here and i have a problem...(i thing the solution is simple, but i can't solve this problem alone...)

I have to throw a few checkbox on userform(that is simple) but when i write someting like that :

 if (checkBox1.Checked)
        {
            MessageBox.Show("ok1");
        }
        else if (checkBox1.Checked && checkBox2.Checked)
        {
            MessageBox.Show("ok2");
        }
        else
        {
            MessageBox.Show("co nie tak");
        }

Always got "ok2" MsgBox... Any ideas what i'm doing wrong?

Thx for helping