When you delete a file from your computer, it is taken to the "recycle bin", and to ensure permanent deletion you must empty this recycle bin. After you've emptied the recycle bin there is no way of getting the file back.....or is there?
What happens in reality is that the space occupied by that file is made available for use by Windows, but the file still exists on the hard disk! Unless you're using your computer and downolading or creating new data that file will continue to exist as long as the space is not used. File recovery software can search the hard disk for files that are still present after they were deleted by mistake.
Deleted files and lost data can also be the result of hard disk damage and disrepair which creates "bad sectors". These files and data can also be recovered through file recovery software. Here again the chances of recovery are high as long as the disk has not been used after the data loss. In case of disks with bad sectors, or lost disk partitions, it is also advisable to use file recovery software that comes with its own bootable CD, and is not free.
Free software can still do a good job of recovering lost data and files. PC Inspector File Recovery first scans the hard disk and lists the detected partitions; in the next scan it detects the files that can be recovered. Other free file recovery software are Recuva, Undelete Plus, and SoftPerfect File Recovery. Damaged or corrupt files can be recovered using PC Tools File Recovery or Recover My Files; neither of these is free.
If you have sensitive data, like photos of pretty girls, that you don't want other people to recover from your disks, then use special software to ensure permanent deletion like Eraser.