VS 2010 Databound comboboxes repeating data

Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        Me.Visible = True
        Dim SQL As String = "SELECT stID, stName FROM tblStudent ORDER BY stName"
        Dim Val As String = "stID"
        Dim disp As String = "stName"
        FillCombo(SQL, cboName, Val, disp, "Student")
        FillCombo(SQL, cboStudentName, Val, disp, "Student")
        SQL = "SELECT grID, grName FROM tblGroup ORDER BY grName"
        Val = "grID"
        disp = "grName"
        FillCombo(SQL, cboStudentGroup, Val, disp, "Group")
        FillCombo(SQL, cboRegistersGroup, Val, disp, "Group")
        FillCombo(SQL, cboReportsGroup, Val, disp, "Group")
        FillCombo(SQL, cboAttendanceGroup, Val, disp, "Group")
        FillCombo(SQL, cboMaintGroupName, Val, disp, "Group")
    End Sub
 
    Private Sub FillCombo(ByVal SQL As String, ByVal CBO As ComboBox, ByVal val As String, ByVal disp As String, ByVal tblName As String)
        dbProvider = "PROVIDER=Microsoft.Jet.OLEDB.4.0"
        dbSource = "Data Source=" & Application.StartupPath & "\Student.mdb"
        Conn.ConnectionString = dbProvider & ";" & dbSource
        Conn.Open()
        da = New OleDb.OleDbDataAdapter(SQL, Conn)
        da.Fill(ds, tblName)
        Conn.Close()
        CBO.DataSource = ds.Tables(tblName)
        CBO.ValueMember = val
        CBO.DisplayMember = disp
    End Sub