Windows 7 adds a secure system file deletion feature - (Screenshot)
According to Neowin on October 10, the update that Microsoft has released is a minor upgrade to Windows 7 SP1 , adding the ability to securely delete the data contained in the WinSxS folder.
This is the folder that contains Windows system files, used to recover when Windows fails due to system failure or file failure. In addition, this directory contains many temporary files that users have previously installed SP1 update package.
After downloading the update, users will see the Disk Cleanup utility in Windows 7 with an option to Clean up system files, when clicking on this option Windows will announce which files and packages are updated. Existing on the computer is redundant, and can safely perform deletion.
Currently, this update is available from Microsoft for free at the Microsoft home page.