There's an especially nasty security hole in all versions of Microsoft's Internet Explorer browser that could potentially allow a compromised (hacked) website to take control of your PC. This exploit has been planted in thousands of web pages (but mostly in China, from what I've heard).
Microsoft is publishing a security fix today, Wednesday, and I urge everyone to apply the fix immediately. If "Automatic Updates" is set on your computer then it will be patched without your intervention. If you don't have Windows updates set to automatic (and I typically recommend you don't -- for various good reasons) then be sure to either click on the update icon in the system tray (lower-right corner, by the clock), or select "Windows Updates" from your "All Programs" menu. Try to make sure that you don't end up applying Service Pack 3 (SP3) in this process (see previous post).
All this brings me to yet another reminder to stop using Internet Explorer altogether and start using Firefox. Firefox is a free alternative to Internet Explorer, and is in many ways safer and easier to use. It can import your existing set of favorites, cookies, and homepage(s), and has an excellent set of user-created plugins for enhancing its functionality.
