Locking text box with a checkbox problem

Hi,
I have a form with a check box (and other controls) that when checked and
saved, updates IsChecked field in a field in a Access table while if it is
unchecked and saved, then it goes to uncheck the IsChecked field in the
Access table.

The form when refreshed shows the checked box checked when the database
value of the IsChecked field is on
while it shows the checked box field unchecked whenthe databae value of the
IsChecked field is off.

Now, I am trying to add a functionality in the form. We are assuming that
the IsChecked field in the table is off.

If a user clicks the checkbox then the textbox associated with the form will
be readonly. On saving and coming back
to this page, the checkbox should show checked and locked along with the
text box that would be locked too.

The problem I am facing:

1) The checkbox is not locking on checking it.

2) When the form is refreshed after saving, though the checkbox is shown
checked, neither the textbox nor
the checkbox is locked.
I appreciate any help in advance

CODE: