Appendix A: File Associations

Overview

The bulk of the registry's content is in HKCR, which is where Microsoft Windows XP stores file associations and class registrations. These settings associate different types of files with the programs that can open, edit, and print them. They also register different program classes so that Windows XP can create objects using them.

A large number of the customizations I make on a regular basis are simple ones in HKCR. For example, I like to add commands to the file association for folders so I can open an MS-DOS command prompt with the selected folder set as the current working directory. I've also added commands to the My Computer object so I can quickly access Registry Editor (Regedit) and Tweak UI. If you master the contents of HKCR, the opportunities for tweaking Windows XP so it looks and feels the way you want are boundless.

The root key HKCR is many times more complex than it was back in the days of Microsoft Windows 95, when I wrote my first registry book. I'm not even going to attempt to describe all the different values you find in HKCR. Instead, I'm going to describe the most useful subkeys and values so you can customize Windows XP using the same techniques that I use.