With increasing development and use of computer technology, there is a new disease to worry about. Computer "viruses" program designed to sabotage computers, are infecting computers in corporation homes and universities. These viruses spread exponentially, much like biological contagion, and then disrupt the affected system. The virus secretly attaches itself to the alter files. The damage is generally activated by using computer's clock. Then, any program executed may be exposed to the virus including program spread through telephone connections. Because of the increasing incidents of virus infiltration, businesses and agencies are becoming wary of sharing software. Security policies need to be increased as immunity programs are being developed.