62 Managing Your SystemSystem integrityProtecting against virusesA virus is a program written with malicious intent for the purpose of creatinghavoc in a computer system.Viruses spread through executable files, document macros, or boot sectors.Diskettes used in a contaminated computer can get a virus and transfer thevirus when used in another computer. A virus can also spread through filesdownloaded from bulletin boards or the Internet.Some viruses may only cause your system to beep or display messages orimages on the screen. Other viruses are highly destructive, and corrupt or erasethe contents of your files or diskettes. To be safe, never assume any virus isharmless. Always protect your system against viruses.To protect your system against viruses:n Use Norton’s ® AntiVirus to scan your computer regularly. Make sure toupdate Norton’s ® AntiVirus periodically to keep up with new viruses.n Make backup copies of all files and write-protect the diskettes. A viruscannot infect a write-protected diskette.n Obtain all software from reputable sources and always scan new softwarefor any viruses before installing it.n Be cautious about files you receive in e-mail or download from a networkor the Internet. If you download a file, use your virus checking softwareto scan the directory on your computer that contains the downloadedfile before you open the file.n If you have doubts about the source of a Microsoft ® Word or Excel file,disable the file macros before opening the file. Word and Excel are setby default to warn you if a document you are about to open contains amacro that might have a virus.Important To protect your system against electrical problems andphysical hazards such as heat, moisture, and dust. Also,to protect it against less obvious hazards such as virusesand hardware overloads.