Normal File Deletion is NOT secure.
Many people believe that emptying the recycle bin will delete a file forever. This is not true, when you delete a file and empty it from the recycle bin, the file is in fact still on your hard drive. The only thing that happens when you empty the recycle bin is that Windows marks the area where the file is on the hard drive as overwriteable so that it can reuse the space when necessary. Deleting files merely removes the file system's pointer to the file, ALL THE DATA REMAINS ON YOUR HARD DRIVE. This allows special data recovery software to be able to actually undelete the file and view all of its original contents. Data recovery or forensic software can easily recover the files you delete. Your sensitive files may also be vulnerable to advanced recovery techniques, even when overwritten, by analyzing latent magnetic traces. Prevent hackers and identity thieves from going through your deleted files and finding your passwords, credit card numbers, and other private information.
Delete Files Permanently is easiest and fastest way to securely delete (or "wipe") sensitive files from your hard drive. You can be assured that once you delete a file with Delete Files Permanently, it will be gone for good, cause data will actually be overwritten several times using specialized methods to prevent data recovery software from being able to undelete the file.