When you delete a file all the OS does in its file address table is to put a zero string in place of the first character of the files address name. So actually the file is not deleted, but the space is marked as empty. When another file is written to the same address on the Hard drive or whatever storage device you are using, it just overwrites the byte address names of the file and writes over the existing file with the new one. Now to recover a deleted file it must meet some criteria.
1. it should'nt have been overwritten so many times. so that the OS can reconstruct the file and the rewrite the first character of its address to the original figure instead of zero.
with the microsoft operating systems, should you delete a file into the recycle bin, it is actually not deleted but kept in the recycle folder, and when that file is deleted from the recycle folder it is written into the system restore folder, if and only if the file is not larger than the system restore allocated memory. if it is larger it is deleted with a zero byte address thing described above.
so if your file was quite small then try a system restore to a date before you deleted it from the recycle bin and the file will be restored into the recycle bin.
How ever if the file size was quite larger than the restore size allocated then you have to use third party disc recovery programs..
these programs search over a storage device and find all files with zero as the beginning of their address (meaning they have been deleted) and then it finds the file attributes of the file (that is name, size, image preview , etc) and presents it to the user. and if it is the file you are searching for it will and can restore the file by rewriting its first character of address name to anyother value other than zero bit. but the ability to recover the files become less probable if it is a long time you deleted it, that is the file may have been written over so many times. so if the file is not recovered by the system restore you can try some of the third party recovery programs like File Restore.
finally you can get file recovery companies to recover your files if they are that much important. the will try and read every byte of data that has ever been written to the computer and try different numbers as their address name beginnings so in the end they can get your file back for you...
in all this you should realize that computers are very nitty... they never delete your files,, they just tell you it is not there anymore but it would be somewhere waiting for the one who can see it to access it......
Good Luck and God Speed..