The Windows Registry is a database of settings used by Windows XP and the individual applications that run on it. Knowing how to access and modify the Registry effectively is important for troubleshooting, customizing, and unlocking hidden features in Windows XP.
An amazing amount of what one might assume to be “hardwired” into Windows — the locations of key directories, the titles of on-screen objects such as the Recycle Bin, and even the version number of Windows XP reported in Control Panel — is actually the product of data stored in the Registry. Change a setting in the Registry and key parts of your system can be affected; for this reason, Microsoft passively discourages tampering by providing only minimal user documentation on the Registry Editor, and no documentation at all on the structure of the Registry itself.
Despite the enormous potential for harm, the Registry is fairly robust, and for every entry that you can wreak havoc by changing, there are hundreds that you can change with impunity. Nonetheless, you should back up the Registry files before making significant changes with Registry Editor. See Section 8.5, later in this chapter, for details.
The Registry is normally consulted silently by the programs (such as Explorer) that comprise the Windows user interface, as well as by nearly all applications. Programs also commonly write varying amounts of data to the Registry when they are installed, when you make changes to configuration settings, ...