How To Really Delete PC Files
On Microsoft Windows, when you delete a file the default behavior is to send the file to the Recycle Bin, and it will stay there until you actually empty the Recycle Bin (and you can readily restore it from the bin if you need to in the interim). Once you empty the Recycle Bin, it's gone, right? Well, yes and no; the file is no longer visible to you and you can't get it back by normal means, but until that area of the hard drive is used for something else, the file (or at least parts of it) are still there and could be recovered if someone had the right tools to do so. You can do a more thorough job of erasing deleted files with the free tool CCleaner, which is usually used to clean up "junk" files on your computer.
Then, under the "Secure Deletion" option, check "Secure file deletion" and choose the number of "passes" from the drop-down menu - I selected 3 passes, which should be fine for a modern hard drive without taking a long time to complete. The more "passes" you select, the more times the data is overwritten, but this can take many minutes if you use the extreme settings.
In use, just right-click on the Recycle Bin and instead of "Empty Recycle Bin", choose the "Run CCleaner" option - you will notice the CCleaner icon flashing away in the system tray for a short time, after which the files will be gone. Using this option, the files to be deleted are actively overwritten and will be much more difficult to recover. Impossible to recover? Who knows what the government boys have in their toolbox...