prueba así
Option Explicit
Public rst As ADODB.Recordset
Public sSQL As String
Public sConex As String
Private Sub Command1_Click()
sSQL = "SELECT * FROM Users WHERE " & _
"UserName='" & Replace(txtUserName.Text, "'", "''") & "' AND " & _
"Password='" & Replace(txtPassword.Text, "'", "''") & "'"
rst.Open sSQL, sConex, adOpenDynamic, adLockOptimistic
If rst.EOF And rst.BOF Then
MsgBox "Invalid user name/password."
Else
Select Case (rst!Nivel)
Case 1:
Form1.Show
Case 2:
Form2.Show
End Select
End If
rst.Close
End Sub
Private Sub Form_Load()
Set rst = New ADODB.Recordset
sConex = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" & Replace(App.Path & "\db.mdb", "\\", "\")
End Sub
obviamente hay mejores formas de trabajar