[Question]

Public Class Form2

    Public Function FileFolderExists(ByVal strFullPath As String) As Boolean
        'Check if file/folder exists_I do not take credits for this
        On Error GoTo EarlyExit
        If Not Dir(strFullPath, vbDirectory) = vbNullString Then FileFolderExists = True

EarlyExit:
        On Error GoTo 0

    End Function

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnrg.Click
        'Register Requirements
        If TextBox1.TextLength < 3 Or TextBox2.TextLength < 3 Or TextBox3.TextLength < 3 Or TextBox4.TextLength < 3 Or TextBox5.TextLength < 3 Then
            MsgBox("Mais Letras num dos campos... Mínimo 3") 'Minimum 3 letters
        ElseIf TextBox5.Text <> TextBox4.Text Then
            MsgBox("Passes não coincidem") 'Portuguese warning meaning "Pass words are not equal"
        End If
        'Creating the "Main" folder
        If FileFolderExists("C:/Manel/") Then
            MsgBox("Yh, existe") 'Saying it exists
        End If
        'If it doesn't
        If FileFolderExists("C:/Manel/") = False Then
            System.IO.Directory.CreateDirectory("C:/Manel/")
            MsgBox("Pasta Criada") 'folder created
        End If
        If FileFolderExists("C:/Manel/" + TextBox3.Text + ".txt") Then
            MsgBox("User Já existe") 'User already exists warning
            Form1.btnregist.PerformClick()
            Me.Close()
        ElseIf FileFolderExists("C:/Manel/" + TextBox3.Text + ".txt") = False Then
            MsgBox("Passo 1 Completo") 'step 1 accomplished
            System.IO.File.Create("C:/Manel/" + TextBox3.Text + ".txt") 'creating user file
        End If
        'Writting User info
        Dim FILE_NAME As String = ("C:/Manel/" + TextBox3.Text + ".txt")

        If System.IO.File.Exists(FILE_NAME) = True Then
            Dim objWriter As New System.IO.StreamWriter(FILE_NAME)
            objWriter.Write("Nome:" + TextBox1.Text + "|||" + "Email:" + TextBox2.Text + "|||" + "User" + TextBox3.Text + "|||" + "Pass:" + TextBox4.Text)
            objWriter.Close()
            MsgBox("User Criado") 'User created
            'Oh btw, in objwriter.write I don't know how to make a line drop so I used ||| How do I make one?
        Else
            MsgBox("Erro") 'Error warning
        End If

    End Sub
End Class

The process cannot access the file 'C:\Manel\ahah.txt' because it is being used by another process.

 Dim objWriter As New System.IO.StreamWriter(FILE_NAME)