'Add this code to lock the fields when you move record to record.
Private Sub Form_Current()
Call LockFields
End Sub
'Add this for each text box to lock it after data is initally entered.
'Do not add this code to each field if you want to allow them to
'Edit the data and have the locks in place after they have gone
'to a new record.
Private Sub txtField1_AfterUpdate()
Call LockFields
End Sub
Private Sub LockFields()
'Add each field you want to lock here.
txtField1.Locked=(Nz(txtField1,"")<>"") 'If txtField has data this evaluates to True, when it doesn't have data it evaluates to false.
End Sub