Option Explicit
Public Const sDir As String = "G://Dir"

Public Declare Function sndPlaySound Lib "winmm.dll" _
        Alias "sndPlaySoundA" (ByVal lpszSoundName As String, _
           ByVal uFlags As Long) As Long

Function listFiles(ByVal sPath As String) As Variant

    Dim vaArray     As Variant
    Dim i           As Integer
    Dim oFile       As Object
    Dim oFSO        As Object
    Dim oFolder     As Object
    Dim oFiles      As Object

    Set oFSO = CreateObject("Scripting.FileSystemObject")
    Set oFolder = oFSO.GetFolder(sPath)
    Set oFiles = oFolder.Files

    If oFiles.Count = 0 Then Exit Function

    ReDim vaArray(1 To oFiles.Count)
    i = 1
    For Each oFile In oFiles
        vaArray(i) = oFile.Name
        i = i + 1
    Next

    listFiles = vaArray
End Function

Function playWav(sPath As String)
    If Dir(sPath) = "" Then
        Exit Function
    End If
    sndPlaySound sPath, 1
End Function

Sub random()
    Static dirArray As Variant
    Static start As Integer
    If start = 0 Then
        dirArray = listFiles(sDir)
        start = start + 1
    End If
    Dim p As Integer
    Dim random As Integer
    random = Int((UBound(dirArray)) * Rnd())
    p = 0
    Call playWav(sDir & "/" & dirArray(random))
    MsgBox (UBound(dirArray))
    If UBound(dirArray) > 1 Then
        For p = random To UBound(dirArray) - 1
            dirArray(p) = dirArray(p + 1)
        Next p
        ReDim Preserve dirArray(0 To (UBound(dirArray) - 1))
    Else
        Call playWav(sDir & "/" & dirArray(random))
        start = 0
    End If

End Sub