If you receive an e-card for Valentine's Day this year, make sure it's authentic and you know who the sender is before opening it, the FBI warns. Increasingly, e-card notices with spoofed addresses are being used to trick people into clicking on links that download malicious programs to their home or office computers.

At the same time, a new version of an old virus hoax is circulating which warns users not to open messages entitled "POSTCARD." The alert claims the supposed virus has been classified "the most destructive ever" by Microsoft, which is untrue. Some versions even include a link to Snopes.com supposedly verifying the threat. But read carefully -- the verification is of a different virus, not this bogus alert.