Scammers are constantly coming up with new and creative ways to wreck computer security. As I report over at APC, the latest hoax to hit Australia is a telephone call claiming to be from either Microsoft or a security software firm, saying that an infection has been detected on your PC and offering to walk you through the fix process. Unsurprisingly, far from fixing the PC, the process completely compromises the machine, making it ripe for further exploitation. Adding insult to injury, the caller then asks for credit card details for a service fee. While most Lifehacker readers are probably savvy enough to avoid this kind of scam, it might be worth mentioning to any credulous friends or relatives. If you're looking to keep your machine secure, check out our Hive Five on the best antivirus software.