In the AfterUpdate event of each of the check boxes you will need to check
the current value of the check boxes in question and change them if needed.
To get to the After Update event, with the form open in design view go to
the Properties sheet for the check box. Double clicking the check box when
it is NOT currently selected should take you there. Go to the Events tab and
in the drop down box next to After Update choose [Event Procedure] and click
the ... button to the right of it. This will take you into the Visual Basic
editor. You will need to use some If statements to check the value of the
check boxes and change them if necessary.
Example:
If Me.chkOtherCheckbox1 = True Then
Me.chkNone = False
End If
If Me.chkOtherCheckbox2 = True Then
Me.chkNone = False
End If
You would do this for each of the other check boxes. You will have to check
all of the other check boxes in each of the check boxes After Update event.
In the After Update event of the None check box you would do something
similar.
Example:
If Me.chkNone = True Then
Me.chkOtherCheckbox1 = False
Me.chkOtherCheckbox2 = False
Me.chkOtherCheckbox3 = False
Me.chkOtherCheckbox4 = False
End If