How do I recover missing song files from my iTunes folder?

Some music files have disappeared from the folder I have synced with my iTunes library. I searched my entire computer, including the recycling bin, and used various recovery programs and found nothing. There is a slight possibility that I deleted them but if I did I would've been able to recover them. I did not download the songs from iTunes so it would be too much of a hassle to redownload them all. How can I get them back?