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Windows does not have a built-in secure destruction tool, but they offer there are many applications which can be downloaded for this purpose. One of these tools is Eraser. To download Eraser, click "downloads," then choose the version listed under "Stable Versions" 
Once the download has completed, open the desktop shortcut. You will see this screen:
Click the small triangle next to Eraser Schedule. Then select New Task. In the window that opens, select Run Immediately and then click Select Data. 
This will open a browsing window. For "Erasure Method," choose "Pseudorandom Data (1 Pass)." Under "File" click "Browse" and find the file you want to securely delete In this example, we will delete "Secure Information" from "My Documents."
Click OK to add the file to the Data Set. When you press "OK," the file will be deleted. At this point, you will not be able to recover the file, so make sure that you have selected the correct file before pressing OK.
Secure Deletion for Macs
Macs have a built-in secure destruction tool. To securely delete files, put them in the Trash.
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