If you're running an older version of the Adobe Flash player, you may be at risk of having your computer compromised. I just upgraded my version of Flash (running in Firefox & Internet Explorer) to 9.0.124.0 to help secure my machine.
Visit the Adobe website to determine which version of Flash you're running...
You can download the Flash Player at the Adobe website...
Here's a link to the related Cyber Security Alert from The United States Computer Emergency Readiness Team...
Anyway, this post is a heads up. If you think you're not at risk because there's nothing of value on your computer, know that gamers are prime targets for this type of attack. If your Guild Wars or World of Warcraft password is stolen, your account could be cleaned out. You might want to read up on this issue and see if your computer is safe.