First you have to check if you have deleted the files using Shift+Del option or simple delete. If you didn’t used Shift+Del you have more chances to recover your data. As the files are still there in the Recycle bin from where you can recover the deleted files. But if you have used Shift+Del option while deleting your files or the size of your file is large enough that Recycle Bin is not able to carry that file you have to use some alternate methods.
There are many free data recovery software which can recover permanently deleted files, but my favorite is Recuva.