Maintaining and Cleaning Your System 23Protecting against virusesA virus is a program written with malicious intent for the sole purpose ofcreating havoc in a computer system. It attaches itself to executable files orboot sectors, so it can replicate and spread. Some viruses may only causeyour system to beep or display messages or images on the screen. Otherviruses are highly destructive and corrupt or erase the contents of your filesor diskettes. To be safe, never assume any virus is harmless.Viruses spread through direct contact with executable programs or bootsectors. Diskettes used in a contaminated system can get a virus andtransfer the virus when used in another system. A virus can also spreadthrough programs downloaded from bulletin boards or the Internet.• Obtain an anti-virus program and scan the system regularly.• Make backup copies of all files and write-protect the disks.• Obtain all software from reputable sources and always scan newsoftware for any viruses prior to installing files.If you suspect your system has been infected, find and remove the virusesimmediately using an anti-virus program. Next, turn off your system andleave it off for at least 15 seconds before turning it back on. This is the onlyway to ensure the virus does not remain in your system RAM.To protect your system against viruses