Dim bOK2Use As Boolean

 Private Sub btnOK_Click()
     Dim bError As Boolean
     Dim sSName As String
     Dim p As DocumentProperty
     Dim bSetIt As Boolean

     bOK2Use = False
     bError = True
     If Len(txtUser.Text)  0 And Len(txtPass.Text)  0 Then
         bError = False
         Select Case txtUser.Text
             Case "user1"
                 sSName = "Corp"
                 If txtPass.Text < "u1pass" Then bError = True
             Case "user2"
                 sSName = "Elect"
                 If txtPass.Text < "u2pass" Then bError = True
             Case Else
                 bError = True
         End Select
     End If
     If bError Then
         MsgBox "Invalid User Name or Password"
     Else
         'Set document property
         bSetIt = False
         For Each p In ActiveWorkbook.CustomDocumentProperties
             If p.Name = "auth" Then
                 p.Value = sSName
                 bSetIt = True
                 Exit For
             End If
         Next p
         If Not bSetIt Then
             ActiveWorkbook.CustomDocumentProperties.Add _
               Name:="auth", LinkToContent:=False, _
               Type:=msoPropertyTypeString, Value:=sSName
         End If

         Sheets(sSName).Visible = True
         Sheets(sSName).Unprotect (txtPass.Text)
         Sheets(sSName).Activate

         bOK2Use = True
         Unload UserForm1
     End If
 End Sub

 Private Sub UserForm_Terminate()
     If Not bOK2Use Then
         ActiveWorkbook.Close (False)
     End If
 End Sub