What is ActiveX?
Microsoft uses the term ActiveX to describe a number of its COM technologies. However, when most people say "ActiveX", they are really referring to ActiveX controls, Microsoft's answer to Java applets. Like applets, programs that use ActiveX controls run on the client computer, not the server.
ActiveX controls are small program building blocks that can be used to create distributed applications that work over the Internet through web browsers. Examples include customized applications for gathering data, viewing certain kinds of files, and displaying animation.
ActiveX and ActiveX controls are similar in that they are both designed to be downloaded and executed by web browsers. The difference is that while ActiveX controls can interface with Microsoft Windows more effectively than Java, they offer very little cross-platform support.
One of the main advantages of ActiveX components is that they can be re-used by many applications (referred to as component containers). Unfortunately, that also means that the component can be re-used by an attacker to run malicious code and gain access to critical files.
Because so many ActiveX controls have turned out to be malicious, Microsoft designed Internet Explorer 7 so that it displays a warning every time a site attempts to use an ActiveX control. It's up to the user to decide whether or not the request comes from a trustworthy source.
For those not technically inclined, or for those who want to improve their computer performance overall, it is suggested that you download PC Health Advisor. It will scan your computer for any issues it has and fix the problems it has detected.