Visual Basic - sql 2008 validar user and password

Option Explicit

Private cnn As ADODB.Connection

Private rst As ADODB.Recordset

Private Sub CMD_LOGIN_Click()

Dim tField As ADODB.Field

Dim USER, KEY As String

USER = TXT_USER.Text

KEY = TXT_KEY.Text

Set cnn = Nothing

Set rst = Nothing

Set cnn = New ADODB.Connection

Set rst = New ADODB.Recordset

cnn.Open "Driver={SQL Server};Server=VKSVR02\VKSQL2008;Database=006;Uid=" + TXT_USER.Text & ";Pwd=" & TXT_KEY.Text & ";"

rst.Open "SELECT USUARIO FROM vk_users", cnn, adOpenDynamic, adLockOptimistic

'validar usuario y passwowrd

'si los datos son correctos

    MsgBox "Bienvenido", vbExclamation

    Unload Me

    Form1.Show

'si los datos son incorrectos

    MsgBox "Error", vbCritical

rst.Close

cnn.Close

End Sub