When most people need to delete a file they simply place it in their Windows recycle bin and empty the bin or delete it using the shift delete function. But does this process permanently delete files? Actually it does not, when you simply delete a file on a Windows based computer either from your internal hard drive or other digital media connected to that computer such as a USB flash drive, all you accomplish is to mark the area of the digital storage that holds that file as now available for more information. Slowly, as new information overwrites the old, the original file content is destroyed.
But if your objective was to remove all traces of that information, you have completely failed as almost any data recovery program can quickly read and restore that information. To permanently delete files what you will need is called a file shredder or drive wipe program. These programs will purposely write random information into the area your deleted file was originally stored. The program to erase files then does this over writing process repetitively until it is a mathematical impossibility to reconstruct the original file.