Please mark updates to your post, and tell us what happens, be more descriptive in your posts please (previously linked to How do I post a question effectively?). Try using the spy.pl to get the window class, e.g.

#!/usr/bin/perl
use strict;
use warnings;
use Win32::GuiTest qw(FindWindowLike GetWindowText);

my @windows = FindWindowLike(undef, "", "Notepad++");

for (@windows) {
    print "$_>\t'", GetWindowText($_), "'\n";
}
[download]

output:

1442758>        'D:\junk\gui.pl - Notepad++ [Administrator]'
[download]