A typo in your original code continued into Jim's

> Private Sub Worksheets_Calculate()

Private Sub Worksheet_Calculate()


When you say "Changing the cell's value" if the cell is not a formula
changing it's value will not trigger a calculation event. So use the Change
event

Private Sub Worksheet_Change(ByVal Target As Range)

If Not Intersect(Target, Range("a1")) Is Nothing Then
CheckBox1.Visible = UCase(Range("A1") = "ABC")
End If

End Sub

As the code is in a worksheet module everything defaults to the sheet, even
if it's not the active sheet. For clarity could qualify with Me

Regards,
Peter T


"yoram" <yoramsk@gmail.com> wrote in message
news:1138048027.329955.318120@g14g2000cwa.googlegroups.com...
> Thanks for the prompt response. Unfortunately, the code still doesn't
> work for me. Changing the cell's value doesn't make the checkbox
> visibile/invisible. I am running 2002 and tried with protection on/off.
>