Source: How-to-geek
Hacking the registry allows you to tweak many things in Windows, such as the adding and removing items from the context menu, enabling and disabling Windows features, customizing the Control Panel, and many other items.
We have documented a large collection of registry hacks and here is a list of 20 of the best hacks.
NOTE: If you are not comfortable making changes to the registry, you should not do so. In any case, before hacking your registry, be sure you back it up. We also recommend creating a restore point you can use to restore your system if something goes wrong.
Add the Registry Editor to the Control Panel
The first hack we will show you is one that might be useful when applying the rest of the hacks in this article. Instead of using the Search box on the Start menu every time you want to access the registry, you can do so using an icon in the Control Panel.
The following article shows you a registry hack that adds the registry editor as another option in the Control Panel. This hack works for any version of Windows.
How to Add Registry Editor to Control Panel
Add Any Application to the Windows Desktop Right-Click Menu
If you like a clean desktop, you can add applications to your right-click menu for quick and easy access and avoid adding icons to your desktop.
Here is a registry hack that shows you how to add an application to the right-click menu using Notepad as an example.
How to Add Any Application to the Windows Desktop Right-Click Menu
Add “Open with Notepad” to the Context Menu for All Files
Speaking of Notepad, we covered a registry hack that allows you to add an “Open with Notepad” option to the context menu for all files.
This hack allows you to open unknown files without having to go through a large list of known applications.