Login Type Windows Form Using SQL?

What I'm trying to do is have a login type windows form to take a user name and password then compare these with data in the db then open an admin type form. I've been trying to get this to work for a few days now with no luck, about 90% of the code below is a peice together from various forums trying to get it to work. I no longer get an error 26 connection cant be made or what may have you, but now I get "Login failed for user ''.", not quite should what this means or how to go about it.

Private Sub LoginB_Click(sender As System.Object, e As System.EventArgs) Handles LoginB.Click
Try
Dim con As New SqlConnection("Data Source=.SQLEXPRESS;Database=C: cdb cdb.sdf;")
Dim cmd As New SqlCommand("SELECT Username, Password FROM(Users) WHERE (Username = '" & UserTXT.Text & "') AND (Password = '" & PassTXT.Text & "')", con)
[Code] .....

DB has no user/pass needed to open... I think, I didn't set one and the whole app doesn't use one and loads binded data within another form without any problem whatsoever?