If an email about a virus contains the phrase, "This is the worst virus announced by CNN, it has been classified by Microsoft as the most destructive virus ever" then it is a hoax.
Every single virus hoax email contains those lines.
All this spreading of miss information really annoys me. If you get an email about the worst virus ever "reported on CNN and confirmed by Microsoft" then it is fake. If you get an email about a virus, do a search on McAfee, Symatec, google etc to see if its real or not. Don't just blindly panic and send it on to anyone you've ever met ever.
And that's not strictly true Integra. If a friend's computer is infected, it may send an email to all the people in its address book, which means you will get an unexpected attachment from a friend. The bottom line is, even if you know who its from, don't open any attachments unless you know exactly what it is.