Deleting files, or even formatting the disk, is unlikely to remove this information. In essence, deleting a file (even after emptying the "recycle bin") is merely a bookkeeping exercise. The information is still in the computer. It is just not accessible through the Windows interface. Passwords, access codes, credit-card numbers, confidential data, etc., can still be retrieved with a piece of software that can be downloaded from the Internet and a fair amount of patience.
The disk should be totally scrubbed before handing over the laptop. A number of utilities that perform the above task are readily available. VASSILIS PREVELAKIS, PhD
Assistant Professor, Computer Science