It is time to make sure your patches have been run again. You will want to make sure that all of your Microsoft Windows patches have been applied. You will also want to check on any Adobe software installed on your system. Most notably Flash Player, which just had an important security fix released this past Tuesday.
The bug fixed in Internet Explorer was also a critical security issue, and should be addressed right away. This issue affects just about all versions of Internet Explorer. You can find more details about the issue on the Microsoft Security Bulletin page.