[Tip:] How to securely delete files form your Windows 7 Computer

[No Warranty]

Download CCleaner:
CCleaner - PC Optimization and Cleaning - Free Download

Set CCleaner's "Secure file deletion (Slower)" option in settings.

CCleaner will write 0's over the data with an X amount of passes that you can set. Make sure you have CCleaner set to deleting files to the Recycle Bin or you will not have this option.