This Small Code Helps us to Rename file in the Folder… Be Carefull with it..

 If Directory.Exists(TextBox1.Text) Then
            If Not TextBox2.Text = "" Then

                Dim str As String
                Dim ct As Integer
                ct = 0
                Try

                    For Each element As String In Directory.GetFiles(TextBox1.Text)
                        ListBox1.Items.Add(element)
                        str = TextBox1.Text & "\" & TextBox2.Text & " " & ct & ".jpg"
                        File.Move(element, str)
                        ct += 1
                    Next
                Catch ex As Exception
                    MsgBox(ex.ToString)
                End Try

                For Each element As String In Directory.GetFiles(TextBox1.Text)
                    ListBox2.Items.Add(element)
                Next
            Else
                MsgBox("Value Missing")

            End If
        Else
            MsgBox("Directory Not Found")
        End If

Textbox1 gets the folder name and textbox 2 gets the custom file name… suppose if folder name is,

c:\myname\myfiles

and if all files inside my files should be renamed to file 1, file 2 etc.. then in textbox2 we should give file. Be Careful with Extensions..