Option Compare Database

Private Sub Command1_Click()
If IsNull(Me.txtLoginID) Then
    MsgBox "Please enter LoginID", vbInformation, "LoginID required"
    Me.txtLoginID.SetFocus
ElseIf IsNull(Me.txtPassword) Then
    MsgBox "Please enter password", vbInformation, "Password Required"
    Me.txtPassword.SetFocus
Else
    'process the job
   If (IsNull(DLookup("UserName", "Users", "UserName ='" & Me.txtLoginID.Value & "'"))) Or _
    (IsNull(DLookup("Password", "Users", "Password ='" & Me.txtPassword.Value & "'"))) Then
        MsgBox "Incorrect LoginID or Password"
        Else
        MsgBox "Login and Password correct"
        DoCmd.OpenForm "mainmenu"
        End If
    End If
End If

End Sub