Knowing how to reference things will help you achieve this, CJ_London gave you a link and you say you tried everything but didn't mention what you tried. You have not done anything for what we know.
Check the attached database. Hiding controls in forms is easy, you just reference the control and then add .visible = false
There is one problem, though, hiding a control with focus can't be done, so you have to first move the focus to some other control before attempting to hide it.