If you use a computer to handle any sensitive information, it is important to take special care when you decide to give away, sell, or discard the computer. Some of the most egregious instances of public disclosure of confidential clinical information have taken place when computers were resold or discarded. In some cases, where no attempt was made to erase the computer's hard disk, the breach of patient privacy can be attributed to plain carelessness. But a conscientious practitioner may also cause a privacy breach by not realizing that the usual technique of “deleting” a computer file from a hard disk is not adequate when a computer leaves the custody of the original owner.

On Windows system, a deleted file is not actually removed from the computer's disk. Instead, the part of the disk where the file resides is marked as “unused,” but the data remain intact until the computer decides to reuse all or part of that area of the disk. Until that happens, the data can be easily recovered by a skilled person. In fact, even after the old data are overwritten by new data, the old data—which still leaves traces under the new data—may still be recovered using special techniques!

In order to make the data truly inaccessible it is important to use a special erasing technique by which the data to be erased are overwritten multiple times. One very good program for this purpose is an open source (free) program called “Eraser,” which can be found at or at .

However, if the computer has broken so that it cannot be restarted to run an erasing program, then it is important to remove and physically destroy the computer's hard disk before disposing of the computer.