What Is the Registry?

The Windows XP Registry is a database in which Windows and application programs store startup information, hardware settings, user preferences, file locations, license and registration information, last-viewed file lists, and so on. In addition, the Registry stores the associations between file types and the applications that use them. For example, the Registry holds the information that tells Windows to use Media Player when you click on an MPG movie file. In the early days of DOS and Windows, programs stored this kind of information in a random collection of hundreds of files scattered all over your hard disk. (Remember CONFIG.SYS?) Thankfully, those days are now only a dim memory.

Most of the time, you can get by without giving the Registry a second thought, because almost every useful Registry entry is set from a Control Panel applet, an application's preferences dialog, or Windows Setup. From time to time, though, you might have to roll up your sleeves to find the location of an errant device driver, you might need to remove an unwanted startup program, or you might just be curious what kind of information Microsoft Office keeps on file about you. This chapter tells you how to go on these kinds of missions.

Two Different Views

One of the advantages of having two authors for this book is that you get two viewpoints. I (Brian) must confess I am a card-carrying Registryphobe; I think Registry tweaking is dangerous and minimally useful. As far as I'm concerned, the Registry is best left alone. I make my living programming with my computer, and the less fancy and more stable it is, the better. "Stock" is the way for me.

For my co-author Bob, who also makes his living with his computer, the Registry is a tweaker's paradise of undocumented adjustments and fascinating Windows trivia. He can change file locations, tune up networking performance, and generally adjust his computer to be "just so." To each his own! We'll both have our say here in telling you how to be careful with the Registry and in showing you how to work with it effectively.