How can i recover my mp3?!

Hello,

just yesterday i went to download a new program so i could download mp3s onto my computer, to put them onto my sony mp3 player. When i downloaded this new program, it came up with ALL my mp3s in its library to share with others. i didn't want them to be shared so i deleted them all out of the library. once i deleted them, they ended up getting deleted from the folder where they were all saved to, and they got deleted out of my windows media player. So i thought i could upload them from my mp3 player BACK to my computer. i plugged it in, and sure enough there were all my songs. My windows media player automatically starts to sync to my mp3 player, and for some reason when it went to sync it ended up deleting a majority of the songs off of my player. i really just need step by steps to find out where all my mp3s went. they aren't in my trash can, but other then that i have no idea how to do get them, or for that matter if i can. hopefully someone can PLEASE help me!