Q&A: Protecting a PC From Spam and Spoofs I keep getting e-mail from someone I know, but the messages do not seem to be from him - they are all junk advertisements. Does my friend have a computer virus, and can I catch it on my PC by opening these messages? Your friend's computer may be infected with malicious software that is using his address book to spread itself. It is also possible that someone else has gained control of your friend's account, or that the real sender is forging (spoofing) his address in hopes that the message will get by spam filters. You can keep your computer safer by not clicking on any included Web links or opening any file attachments that may be included in the messages. An up-to-date security program - one that includes antivirus, anti-spyware and firewall protections - can catch many forms of malware. If you do not have a commercial security suite, About.com has a list of free basic antivirus programs. Free versions of anti-spyware programs like Malwarebytes and Spybot Search & Destroy are also available. You should contact your friend with the suspect e-mail account and let him know about the situation. He should also check his machine with anti-malware software for viruses and things like Trojan horse programs. Trojan horse malware can do things like record password keystrokes or even turn the computer into a remote-control machine for someone else. After scanning the computer, he should also change his passwords for e-mail and other services, especially if malware or unfamiliar messages in the e-mail account's out-box were discovered. It can be harder to deal with messages that are merely forging your friend's return address in the sender field. Looking at the full message header to see the originating e-mail address can reveal a spoof; the steps for displaying headers in several mail programs are here. If spoofing is the cause, there is not much you can do, but the PC World site has an article on minimizing exposure to e-mail spoofing.