Enum lastfolder
    last = "C:\carpeta"
End Enum 

    Public Sub C1Button3_Click(sender As Object, e As EventArgs) Handles folderbutton.Click
        Dim folderselect As New VistaFolderBrowserDialog
        folderselect.RootFolder = lastfolder.last
        folderselect.ShowNewFolderButton = True
...
    End Sub

            If System.IO.File.Exists(Temp_file) = True Then System.IO.File.Delete(Temp_file)
            System.IO.File.Create(Temp_file)

The process cannot access the file 'C:\Users\Administrador\AppData\Local\Temp\PlayList_temp.txt' because it is being used by another process.

  Public Sub C1Button2_Click(sender As Object, e As EventArgs) Handles Button1.Click
 
        If Not playerargs = Nothing Then
 
            Dim Str As String
            Dim Pattern As String = ControlChars.Quote
            Dim ArgsArray() As String
            Dim Temp_file As String = System.IO.Path.GetTempPath & "\PlayList_temp.txt"
            Dim objWriter As New System.IO.StreamWriter(Temp_file)
 
            Str = Replace(playerargs, " " & ControlChars.Quote, "")
            ArgsArray = Split(Str, Pattern)
 
            If System.IO.File.Exists(Temp_file) = True Then System.IO.File.Delete(Temp_file)
            System.IO.File.Create(Temp_file)
 
        For Each folder In ArgsArray
            If Not folder = Nothing Then
                Dim di As New IO.DirectoryInfo(folder)
                Dim files As IO.FileInfo() = di.GetFiles("*")
                    Dim file As IO.FileInfo
 
                For Each file In files
                    ' command to writleline
                    'Console.WriteLine("File Name: {0}", file.Name)
                    'Console.WriteLine("File Full Name: {0}", file.FullName)
                    objWriter.Write(file.FullName)
                    objWriter.Close()
                Next
            End If
            Next
 
        If randomize.Checked = True Then
                RandomiseFile(Temp_file)
        End If
 
        Process.Start(userSelectedPlayerFilePath, playerargs)
        If autoclose.Checked = True Then
            Me.Close()
        End If
        Else
        MessageBox.Show("You must select at least one folder...", My.Settings.APPName)
        End If
    End Sub

....
If Not playerargs = Nothing Then
    ....
    Dim Temp_file As String = System.IO.Path.GetTempPath & "\PlayList_temp.txt"
 
    Using objWriter As New System.IO.StreamWriter(Temp_file, false)
        For Each folder In ArgsArray
            If Not folder = Nothing Then
                Dim di As New IO.DirectoryInfo(folder)
                Dim files As IO.FileInfo() = di.GetFiles("*")
                Dim file As IO.FileInfo
                For Each file In files
                    ' command to writleline
                    'Console.WriteLine("File Name: {0}", file.Name)
                    'Console.WriteLine("File Full Name: {0}", file.FullName)
                    objWriter.Write(file.FullName)
                    ' objWriter.Close() 
                Next
            End If
        Next
    End Using ' Flush, close and dispose the objWriter
    ....

Winamp.exe "Argumento 1" "argumento 2" "argumento 3" "más argumentos"

' Pseudocode
For each folder in var.split(ControlChars.Quote)
    for each file in get.folder.files
     appendline.(archivo_de_Texto, file.Name)
  Next

            Dim entries = playerargs.Split(" "c)
            For n As Integer = 1 To entries.Length - 1
                Dim files As String() = Directory.GetFiles(entries(n))
            Next

My.Computer.Registry.SetValue("HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced", "HideDrivesWithNoMedia", 1, Microsoft.Win32.RegistryValueKind.DWord)

static class SafeNativeMethods
{
public static IntPtr HWND_BROADCAST = (IntPtr)0xffff;
public static int WM_WININICHANGE = 0x001A;
 
[DllImport("User32.Dll")]
public static extern bool PostMessage(IntPtr hWnd, int Msg, int wParam, int
lParam);
}
 
public static class Refresher
{
public static void ReloadSettings()
{
SafeNativeMethods.PostMessage(SafeNativeMethods.HWND_BROADCAST,
SafeNativeMethods.WM_WININICHANGE, 0, 5000);
}
}
 
static void ExWin()
{
Form form = new Form();
Refresher.ReloadSettings();
Application.Run(form);
}

       ' Start a drag.
        foldertextbox.DoDragDrop( _
            foldertextbox.Text, _
            DragDropEffects.Copy)

If Me.FindControl("Checkbox1") IsNot Nothing Then

If Me.Panel1.Contains("Checkbox1") = False Then

            With mcheck(i)
                .AutoSize = True
                .TabIndex = 0
                .Location = New Point(0, i * 20)
                .Name = "CheckBox" & i + 1
                .Text = folder.Name
            End With