thanks .
But still does not work.
I have used following code for check box.
Private Sub CheckBox1_Click()
If CheckBox1.Value = True Then

Rows("18:39").Hidden = False
Else
Rows("18:39").Hidden = True

End If

End Sub

i want to protect this sheet but when i protect the sheet , the check box
doesnot work. It gives some error messege.

pmss