[2005] VB.NET and SQL

[QWERTYtech]

Okay, I am using a login form and it has been working for a while now. Whenever I tried running it yesterday and today, it failed. This is the error im encountering. SQLException was unhandled - Database 'T:\AITP NEW\AITP\AITP\users.mdf' already exists.
Could not attach file 'C:\AITP NEW\AITP\AITP\users.mdf' as database 'users'. My code is below. What would be causing this?

Public Class Login
    ' Place this code under your Public Class.  If your form name is Login, then place it under Public Class Login
    Inherits System.Windows.Forms.Form
    Dim iCount As Integer ' this integer is declared to help count the number of imes a user tried to login.
    Dim frmMain As New Form1 ' this line declares a variable that will point the user to the Main Screen upon a successful login.  The second form created is called MainScreen.vb
    'Dim UserLoginInfo As New user
 
    Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles loginbtn.Click
        Dim theConnectionString As New SqlClient.SqlConnection("Server=.\SQLExpress;AttachDbFilename=C:\AITP NEW\AITP\AITP\users.mdf;Database=users;Trusted_Connection=Yes;")
        Dim theSqlCommand As New SqlClient.SqlCommand("SELECT [User_LoginType] FROM [Users] WHERE [User_Name] = @username AND [User_Password] =@password", theConnectionString)
 
        Dim theUsername As New SqlClient.SqlParameter("@username", SqlDbType.VarChar, 50)
        theUsername.Value = Usernametxbx.Text
        Dim thePassword As New SqlClient.SqlParameter("@password", SqlDbType.VarChar, 50)
        thePassword.Value = Passwordtxbx.Text
        theSqlCommand.Parameters.Add(theUsername)
        theSqlCommand.Parameters.Add(thePassword)
 
        'open the connection
        theSqlCommand.Connection.Open()
        Dim theDataReader As SqlClient.SqlDataReader = theSqlCommand.ExecuteReader(CommandBehavior.CloseConnection)
 
        Dim theLoginType As Object = Nothing
        If theDataReader.HasRows Then
            theDataReader.Read()
            'the user exists!! Lets get the logintype:
            theLoginType = theDataReader("User_LoginType")
            'UserLoginInfo.UserType = theLoginType
            'UserLoginInfo.user_info = theUsername
        End If
        theSqlCommand.Connection.Close()
 
 
 
        If theLoginType = "admin" Then
            If accesslvlcmbx.SelectedItem = "User" Then
                Me.Hide()
                frmMain.Show()
                Me.Close()
            ElseIf accesslvlcmbx.SelectedItem = "Administrator" Then
                Me.Hide()
                admin.Show()
                Me.Close()
            ElseIf accesslvlcmbx.SelectedItem = "" Then
                MessageBox.Show("You need to select a login type.", "LoginType", MessageBoxButtons.OK, MessageBoxIcon.Error)
            End If
        ElseIf theLoginType = "user" Then
            If accesslvlcmbx.SelectedItem = "User" Then
                Me.Hide()
                frmMain.Show()
                Me.Close()
            ElseIf accesslvlcmbx.SelectedItem = "Administrator" Then
                MessageBox.Show("You do not have sufficient access. Please select again.", "LoginType", MessageBoxButtons.OK, MessageBoxIcon.Error)
            ElseIf accesslvlcmbx.SelectedItem = "" Then
                MessageBox.Show("You need to select a login type.", "LoginType", MessageBoxButtons.OK, MessageBoxIcon.Error)
            End If
        End If
 
    End Sub
 
    Private Sub Cancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Cancel.Click
        Me.Close()
    End Sub
End Class