[VB .NET] how to rename a file correctly?

Hello everyone,
I tried various ways to be able to rename the file "%windir%\system32\oemlogo.bmp" in Windows XP, but all failed.
I do not know what depends so I ask you for help.


this is my code

Code:

    Private Sub DelFile()
        Dim FilePath As String = Environment.GetEnvironmentVariable("systemroot").ToCharArray(0, 3) & "Windows\System32\oemlogo.bmp"
        If My.Computer.FileSystem.FileExists(FilePath) Then
            System.IO.File.SetAttributes(FilePath, IO.FileAttributes.Normal)
            PermessoFile(FilePath)
            My.Computer.FileSystem.RenameFile(FilePath, FilePath & ".bak")
        End If
    End Sub

    Private Sub PermessoFile(ByVal FilePath As String)
        Dim sUserAccount As String = Environment.UserDomainName & "\" & Environment.UserName
        Dim oFileInfo As IO.FileInfo = New IO.FileInfo(FilePath)
        Dim oFileAcl As New System.Security.AccessControl.FileSecurity(FilePath, System.Security.AccessControl.AccessControlSections.Access)
        oFileAcl.AddAccessRule(New System.Security.AccessControl.FileSystemAccessRule(sUserAccount, _
                                                          System.Security.AccessControl.FileSystemRights.FullControl, _
                                                          System.Security.AccessControl.AccessControlType.Allow))
        oFileInfo.SetAccessControl(oFileAcl)
        oFileAcl = Nothing
        oFileInfo = Nothing
    End Sub

Thanks to all.

 

i apologize. I solved.
I was unable to rename the file because it was using to display it in a picturebox.
thanks for your help.
you are very kind.