2: Using the Registry Editor in .NET

Encoder Data Matrix 2d barcode in .NET 2: Using the Registry Editor

Registry Editor is the tool you use to edit the registry directly. You change the registry every time you log on to the computer, but you do it indirectly through Control Panel or the Run dialog box, which updates the registry's list of programs that you've run recently. With Registry Editor, you affect settings without the help of a user interface. That makes Registry Editor one of the operating system's most powerful and dangerous tools. On one hand, you can customize Microsoft Windows XP in ways that aren't possible through the user interface. On the other hand, nothing is checking the settings you change for sanity. Every version of Windows since 3.1 has had a registry editor. The editor in Microsoft Windows 95 can search the registry and has a simple to use interface. Microsoft Windows NT 4.0 has an archaic editor that can't search and is more difficult to use than the editor in Windows 95, but it has capabilities unique to a secure operating system, such as the ability to set permissions on keys and edit more advanced data types like REG_MULTI_SZ. Microsoft Windows 2000 provides both editors, requiring you to switch back and forth to use each editor's unique abilities. Now, with Windows XP, you get the best of both editors in a single program (insert applause for the developers here). Registry Editor in Windows XP is the tool you learn about in this chapter. It's the basis for just about every set of instructions you see in this book. It is also the basis for many solutions you find in Microsoft's Knowledge Base, the solutions that people post to UseNet, and so on. This chapter contains more than just instructions for how to use the editor, though. You'll find useful tidbits of information that come from my own experience using this program, such as how to search better and how to quickly back up settings before changing them, which will hopefully make your experience with the single most powerful tool in Windows XP a great one.

You won't find a shortcut to Registry Editor (Regedit) on the Start menu. You don't want to find a shortcut to Regedit on the Start menu. Imagine what life as an IT professional or power user who supports friends and relatives would be like if Microsoft advertised this program to every Windows XP user on the planet. That's one reason why you find so little documentation about Regedit in Help or elsewhere. That's also why Windows XP provides policies that you can use to limit access to Regedit. IT professionals and power users have great need for Regedit, however it's often the only way to fix a problem or customize certain settings. For example, I recently used a program that changed critical settings while it was running, and then restored them when the program shut down. Unfortunately, the program crashed without restoring the settings and the only way I could get them back to their original values was to edit the registry. Sometimes, it's the only tool for the job. Note Regedit and Registry Editor are one and the same. Regedit.exe is the name of Registry Editor's program file and it is easier to type, say, and read, so I will use the term Regedit for Registry Editor throughout the remainder of this book.

Regedit is in %SYSTEMROOT%, C:\Windows on most computers. Click Start, Run, and type regedit to run Regedit. You don't have to type the path. If you want to start Regedit even quicker, drag Regedit.exe to your Quick Launch toolbar or to the Start button to add it to the top of your Start menu. 33

IT professionals can prevent users from running Regedit. They can set the Disable registry editing tools policy in Group Policy, local or otherwise. When users try to run Regedit, they see an error message that says, "Registry Editing has been disabled by your administrator." Although it's probably not a good idea to prevent the setup program from installing Regedit.exe, you can set the Regedit.exe file's permissions to prevent users from running it or better yet, use Software Restriction Policies to prevent users from running Regedit.exe, regardless of the file's permissions or users' rights. I cover these topics in detail elsewhere in this book. Note For more information about Group Policy and Software Restriction Policies, see 6, "Using Registry Based Policies." To learn the best way to deploy file and registry permissions, see 7, "Managing Registry Security."

NoteAdministrators shouldn't rely on any of these methods to secure the registry completely. These simple barriers don't stop determined users from gaining access to the registry. For instance, dogged users can download shareware registry editors, most of which don't honor the Disable registry editing tools policy. Shareware registry editors also circumvent Software Restriction Policies and permissions that you apply to Regedit.exe. In reality, determined users will always find a way to hack away at the registry, so part of the solution must be a corporate IT policy that you clearly communicate to users.