Such programs have been blamed for the large-scale destruction of programs and data. Tangible damages have been estimated at hundreds of millions of dollars annually, while the intangible costs of reconstructing data cannot be estimated.
Malicious software can damage or destroy both programs and data.
In an open computing environment such as NIH the risk is especially great. Almost two dozen distinct viruses have been identified on the NIH campus. The problem has become sufficiently widespread so that today, everyone who uses a computer should be aware of the problem and know what to do to avoid it. While panic is certainly not called for, every computer user should know in general how computer viruses work, the symptoms of common viruses, basic precautions to be taken, and the different kinds of antiviral software that are available. It is useful to understand the meaning of the different terms used when discussing malicious software.