When you delete files from your PC using Windows Recycle Bin, they don't really go away entirely. Instead, Windows just marks the files as erased and hides them from view until you eventually fill that drive space with something else. If you want to make sure your data is gone for good, use Eraser, a free file deletion utility that uses DoD-grade algorithms to repeatedly overwrite your deleted data until it's practically unrecoverable.
Note: This software used to come in 32-bit and 64-bit versions; it now supports both in a single download. This program is donationware. It is free to try, but the author accepts and encourages donations towards further development.
Click here to Download Eraser
