any help please

@[MoXa].1
it may be that you are using external libraries, if you are using them, the error is that it isn't not able to load them
if you have always this problem, post your code

@Raydenman

this is my code

Imports System.Data.SqlClient
Imports MySql.Data.MySqlClient
Dim MySqlConnection As MySqlConnection
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
MySqlConnection = New MySqlConnection
MySqlConnection.ConnectionString = "server=*******;port=******; user id=******; password=******; database=******"
MySqlConnection.Open()
Dim Myadapter As New MySqlDataAdapter
Dim sqlquary = "SELECT * From Users WHERE username='" & TextBox1.Text & "'AND password='" & TextBox2.Text & "';"
Dim command As New MySqlCommand
command.Connection = MySqlConnection
command.CommandText = sqlquary
Myadapter.SelectCommand = command
Dim Mydata As MySqlDataReader
Mydata = command.ExecuteReader
If Mydata.HasRows = 0 Then
MsgBox("Incorrect username or password.")
Else
Form1.Show()
Me.Hide()
End If
End Sub

@Biesi can you explain more for me!

he said that you can use also PHP to register/login (preferably with custom user-agent), and using webrequest

it's free or what
and how can i use php ? and make register website !

yes, it's free, you can also use XAMPP platform or using free webhosting like 000webhost to host your modules for login and register .