If you’re running Windows, then you should get your system patched ASAP and check that your virus scanner definitions are up to date. Not that you shouldn’t be doing this all the time, but there is a worm called Conficker C that has already infected millions of computers and will allow the author to control those computers on April 1.
Luckily, the world has been mostly spared from really serious attacks. Most viruses, worms and trojans have been written to make the authors lots of money, not necessarily inflict damage on the target computers. But that could change easily. Be afraid and take steps to prevent that from happening to you.
Incidentally if you do not have a virus scanner and don’t wish to pay for one, then there are free ones out there that do the trick just as well. For example, I’ve had great success with AVG Free which is free for non-commercial use.
