   txtValue(Index).BackColor = vbButtonFace
        Else
            txtValue(Index).BackColor = vbWindowBackground
        End If
    End If
    If (chkAuto.Value = Checked) Then
        pCalculateWeight
    End If
End Sub
Private Sub pCalculateWeight()
Dim i As Long
Dim lWt As Long
    For i = txtValue.LBound To txtValue.UBound
        If IsNumeric(txtValue(i).Text) Then
            lWt = lWt + Val(txtValue(i).Text)
        End If
    Next i
    txtWeight.Text = lWt
End Sub

Private Sub txtValue_KeyPress(