No. Any and all viruses are parasitic. There may not be any helpful viruses, but there are certainly a large quantity of harmless viruses, which doesn't infect humans, but rather specific animals or plants.
No. Viruses do not have a lifespan because they never die. A virus does notcontain the 6 characteristics of life. A virus can not be killed either. To be cured of a virus, you must be patient or wait or let your T cells or any other helpful things get rid of the virus.
They do not have an effect on swine flu, but can be helpful if a secondary bacterial infection occurs with the flu or after the flu. Antibiotics have no effect on viruses. The flu is caused by viruses. Antibiotics are for treating infections by bacteria, not for treating infections by viruses.
no computer viruses are good they can make your computer not do commands that you make it to Trojans in particular can disguise them selves as a helpful program and then get information from you, you should install Microsoft security