Computer viruses may affect your computer in different ways, and most do not immediately result in a crashed hard drive. The earlier you recognize the virus, the more likely a professional will be able to perform a successful virus removal that restores your computer to normal again without lasting damage. Symptoms may begin appearing right away, but it is more likely that they will begin to appear within 3 to 6 weeks after exposure to the virus. Knowing what the symptoms of a virus are can help you to catch it early and get help.