I regularly receive forwarded emails from friends quoting some supposed malware (malicious software) threat to my PC. These invariably turn out to be hoaxes, of which the sender is another unwitting victim. Never forward these emails on without checking whether they are genuine - they very rarely are! A good source to check is the F-Secure Hoax Description Database. I'm a fan of F-Secure and use F-Secure Internet Security 2007 to protect my PC, with good results. The F-Secure blogs are a good way of keeping an eye on what's happening out in the malware world.
