How Does a Computer Virus Spread, And How to Prevent it?

How does a computer virus spread?

INFECTED PEN DRIVE, CD AND OTHER STORAGE MEDIA: storage media like compact disc or a pen drive may have a computer virus. Using infected storage medias helps virus to spread from one computer to another.
INTERNET: Viruses can get attached to various types of Internet files, such as, graphics and program files that people download from the internet.
E - MAIL: Viruses are often transferred between computers as e- mail attachments.
COMPUTER NETWORK: The computers on computer networks constantly share information if one file that is being used by several network user becomes infected with a virus. Virus quickly spread on the other us.

Use antivirus software. Scan your computer with antivirus on a regular basis.
Update your virus detection programs frequently in order to contract the new virus.
Scan the downloaded internet file with antivirus software before you use or run them .
If you receive an e-mail attachment you need to scan it before opening it .
Do not open e-mail attachments which you are not expecting some viruses spread himself by sending infected image to all, books. The person sending to the virus might not even now that they are sending you an e-mail at all.
Always maintain a backup of your important files so that in case your computer gets infected.
Always scan the storage media before connecting it to your computer.
If the antivirus detects a virus, clean the virus. But if the software cannot clean it, delete the infected file.
Beware of files from unknown sources. If you receive an unexpected attachment from an unknown source, delete it. Do not accept files from people you do not know Whether it is a via chats, instant communicators or e-mail, it is not a good idea to open any such files.