The 'Antivirus 2008 (or 2009 or 2010)' virus is on the rampage again.
WARNING! WARNING! WARNING!
If you get any kind of popup warning of virus infections in you computer make absolutely sure that it has the name of your antivirus software on it somewhere before clicking anything.
It will look alot like this:

If you get one of these, just close your browser and do NOT click anywhere on the popup!!
You can then google 'Antivirus 2010' (or whatever year it has on the popup) and learn about it and how to remove it if it has gotten into your computer!