Removing Application Tidbits (1)
Many applications leave tidbits behind. Previous sections of the chapter have already told you how to manage some of these tidbits. For example, the “Working with Components” section discusses
application components and the “Following the Flow of Registry Entries’ section describes the inner workings of file associations. This section provides some additional pointers on getting rid of applications you no longer need. It’s important to remember to save these application settings, should you need them later, by exporting and archiving them.
Deleting Old Setup Data
Even after you uninstall an application, many applications leave registry settings in place. The most common registry entries are user or system settings. The “Working with Application Entries” section of the chapter describes how to work with these settings. However, once you get past these settings, you’ll often find other settings left behind. These settings can cause any of the following problems:
Inefficient Use of System Resources As with many other elements of the registry, Windows believes everything it has to say. When the registry tells Windows that there’s an application available to handle a particular file or other need, Windows believes it. Even when the application folder for the application is missing, Windows will faithfully search for it, consuming your time, system processing cycles, and memory. Anything you can do to keep old setup information out of
the registry optimizes Windows.
System Reliability Problems Old registry settings cause more grief than you can imagine. It’s possible for these settings to affect system stability. When your machine thinks it has a resource that no longer exists and the machine tries to use that resource, reliability problems begin to manifest themselves. You won’t always see an outright crash. For all its flaws, Windows does recover remarkably well from single or even double errors. However, as the number of registry errors increase, the fixes for the problem become more problematic and you begin to notice system glitches. At some point, the recovery system becomes overwhelmed and your system begins to crash or exhibit other strange behavior.
Application Reliability Problems Applications receive input from a number of sources in Windows. You don’t see most of the activity that goes on behind the scenes, but your application is constantly interacting with Windows, device drivers, and even other applications. As the number of resource or application interaction errors increases, the reliability of your application decreases. Imagine this scenario. You open a document that contains an embedded document from another application. The application requests server support from the other application through Windows. Unfortunately, you have already uninstalled the other application. Unless the equesting application has good error handling (most don’t) the application will crash—all because a leftover registry entry led the requesting application to believe a server was available for the embedded file.
Security Issues All of the accumulated dirt in a registry can also lead to security problems. For one thing, all of those old entries provide more places for virus, adware, and spyware application entries to hide. The extra registry entries make it harder for antivirus and other helpful applications to locate the applications you don’t want. In addition, older files often contain bugs that let these unwanted applications in the door. For example, even if you aren’t using an older DLL, a registry entry could tell Windows to load it into memory. The second this event happens, your system becomes vulnerable to the attacks the older DLL allows.
Taken From : Microsoft Windows XP Power Optimization