A costly worm that first struck computers on September 18, 2001, and was still around in August 2002. NIMDA is thought to have cost about $500 million in damages as corporations repaired their networks and added virus protection software and other security services. Without any assistance from computer users, the NIMDA worm spread quickly through Windows 2000 computers on the Internet. Bruck, M. The Key to Eradicating Viruses and Bugs. [Online, August 5, 2002.] Entrepreneur.com, Inc. Website. http://www.entrepreneur.com/article/ 0,4621,302155,00.html.