Renan e/randomizer

Imports System.Threading, System.IO, System.Text
Module Module1
    Public path As String
    Public i As Integer = 0
    'Public rnd As New Random
    Sub Main()
        Console.Title = "Black Widow  -  Bulk File Renamer  -  V1.0"
        Console.ForegroundColor = ConsoleColor.Red
        Console.WriteLine("
           /      \
        \  \  ,,  /  /
         '-.`\()/`.-'
        .--_'(  )'_--.
       / /` /`**`\ `\ \
        |  |  ><  |  |
        \  \      /  /
            '.__.'

 Randomize filenames en-masse!
")
        Console.ForegroundColor = ConsoleColor.Gray
        Console.Write(" Enter in path to directory: ")
        path = Console.ReadLine()

        Dim len As Integer = path.Length()
        Dim chkSlash As String = path
        chkSlash = chkSlash.Substring(len - 1)
        If chkSlash.ToString = "/" Then
            path = path.Remove(path.Length - 1)
        End If


        Console.WriteLine("
 Pending...
")
        'Thread.Sleep(2000)

        For Each targFile In Directory.GetFiles(path)
            Dim fileName As String = genJunk(5, 15)
            'Thread.Sleep(500)

            Dim targInfo As New IO.FileInfo(targFile)
            Dim fileExt As String = targInfo.Extension

            Do
                If My.Computer.FileSystem.FileExists(path + "\" + fileName + fileExt) Then
                    fileName = fileName + i.ToString
                Else
                    Exit Do
                End If
            Loop

            Try
                My.Computer.FileSystem.RenameFile(targFile, fileName + fileExt)
                Console.WriteLine(targFile + " ---> " + fileName + fileExt)
            Catch ex As Exception
                Console.WriteLine(" Critical error encountered!")
            End Try

        Next
        Console.WriteLine("
 Task completed! Strike ENTER to finalize.
")
        Console.ReadLine()
        Environment.Exit(0)
    End Sub

    Public Function genJunk(MinLength As Integer, MaxLength As Integer) As String
        Static rnd As New Random()
        Dim validchars() As Char = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLOMNOPQRSTUVWXYZ0123456789".ToCharArray()
        Dim res As String = ""

        For i As Integer = 0 To rnd.Next(MinLength - 1, MaxLength)
            res += validchars(rnd.Next(0, validchars.Length))
        Next

        Return res
    End Function
End Module