Registry

Windows Registry, found on Windows operating system like Windows 7/XP/Vista/2000, is the central database that stores necessary information needed for the operation of Windows. It contains all information and settings for hardware devices, software, and per-user settings and preferences.

The registry is essentially the catalog or reference source for your computer. When you attempt to open a program-for example, your installed software-your computer queries the registry to find where the program is stored. What's more, whenever you make a change to the Control Panel settings, file associations or installed software, registry recorded the changes.

Regular registry cleanup and system optimization is recommended, because without that, Windows registry will get very large and fragmented, which can severely slow down your computer and cause errors even crashes.

Registry Editor

Registry Editor is the tool provided by Microsoft for users to edit Windows registry. Whenever you log on to the computer, you do make a change to registry indirectly. To directly edit Windows registry, just run "regedit.exe" and Registry Editor will pop up.

Since any inappropriate operation made to the registry can lead to serious problems even may cause Windows fails to start, Microsoft or other IT professional never recommend users, especially novice users to edit registry manually (using Registry Editor).

But if you have to do so, remember to backup your registry before you make change. Therefore, you may restore your computer to previous point whenever problems occur.

ActiveX

A loosely defined set of technologies developed by Microsoft for sharing information among different applications. ActiveX is an outgrowth of two other Microsoft technologies called OLE (Object Linking and Embedding) and COM (Component Object Model). ActiveX can be very confusing because it applies to a whole set of COM-based technologies. Most people, however, think only of ActiveX controls, which represent a specific way of implementing ActiveX technologies.

ActiveX controls:

A control using ActiveX technologies. An ActiveX control can be automatically downloaded and executed by a Web browser. ActiveX is not a programming language, but rather a set of rules for how applications should share information. Programmers can develop ActiveX controls in a variety of languages, including C, C++, Visual Basic, and Java. An ActiveX control is similar to a Java applet. Unlike Java applets, however, ActiveX controls have full access to the Windows operating system. This gives them much more power than Java applets, but with this power comes a certain risk that the applet may damage software or data on your machine. To control this risk, Microsoft developed a registration system so that browsers can identify and authenticate an ActiveX control before downloading it. Another difference between Java applets and ActiveX controls is that Java applets can be written to run on all platforms, whereas ActiveX controls are currently limited to Windows environments. Related to ActiveX is a scripting language called VBScript that enables Web authors to embed interactive elements in HTML documents.