Với ThisWorkbook làm code sau:
Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As Boolean)
Sheets("hanghoa").Visible = xlSheetVeryHidden
Sheets("khachhang").Visible = xlSheetVeryHidden
Sheets("nhanvien").Visible = xlSheetVeryHidden
Sheets("nhacungcap").Visible = xlSheetVeryHidden
Sheets("nhap").Visible = xlSheetVeryHidden
Sheets("xuat").Visible = xlSheetVeryHidden
Sheets("hoadonnhap").Visible = xlSheetVeryHidden
Sheets("hoadonxuat").Visible = xlSheetVeryHidden
End Sub
Private Sub Workbook_Open()
frmLogin.Show
End Sub