If it isn't in the recycle bin, nor on your backup, it's not sure it can be recovered. But if you take the disk out and connect it (in an external enclosure) to another PC, there are programs that can try to do it. The reason to do that on another PC that the more you do on the disk (such as installing these programs) the bigger the risk that that data is overwritten.
See the top post (lost and found) in our storage forum http://forums.cnet.com/storage-forum/ for susggestions for programs. Most are not free, but Recuva is.
A google search for NTFS UNDELETE (assuming that partition that you deleted that files from is formatted in NTFS format) will find a lot of 'undelete' programs also. That's maybe easier to start with. Be sure not to pay for shareware until you found out it could find those files (they usually have a demo mode).
It's much easier and more safe to have a backup to get it from.