You can securely overwrite deleted files with a built-in Windows tool - Cipher.exe

To overwrite the deleted data at your PC on a volume by using Cipher.exe, use the /switch with the cipher command:

cipher  /w: C

cipher.exe

Step-1

First of all quit all programs whatever running.

Step-2

Click Start, click Run, type cmd, and then press ENTER.

In windows 8.1 "Windows Key" + R works just as easy as it does in windows 7 and CMD is a lot shorter to type than Command Prompt.

Step-3

Type cipher /w: folder

then press ENTER, where folder is any folder in the volume that you want to clean.

If your data is on a different drive such as a partition labeled D:\ simply substitute C for the correct drive letter. For most people, however, C will be the right choice.

Windows will also advise you to close as many running programs as you can, This will help the window to do a better cleaning up process.  

Here is Complete Reference and guild line about Cipher.exe from Microsoft.

Warning:

Just remember, don't do this on SSD's regularly.   SSD's have limited read/write ability.   If you erase them, you will shorten their lifetime.