Worms Worms are like viruses in that they do replicate themselves. However, instead of spreading from file to file, they spread from computer to computer, infecting an entire system. Users often forward these alerts thinking they are doing a service to their fellow workers, but this causes lost productivity, panic and lost time. This increased traffic can soon become a massive problem in e-mail systems and cause unnecessary fear and panic. Viruses Benign - Malignant Viruses are either benign or malignant.
Some viruses are harmless and do no real damage to a computer or files.
A benign virus might do nothing more than display a message at a pre-determined time or slow down the performance of a computer. Malignant viruses cause damage to a computer system, such as corrupting files or destroying data. As the way people exchange electronic information changes, so does the nature of viruses. For example, the boot-sector virus is on the decline as people move to Windows and Windows NT operating systems. New viruses are able to migrate from Windows 98 to Windows NT and back again.