Windows lets you use the Group Policy to define user and computer configurations for groups of users and computers. With the Group Policy snap-in you can specify policy settings for the following: Registry-based policies, Security options, Software installation and maintenance options, Scripts options and Folder redirection options.
Local Group Policy Editor
The Group Policy Editor (Gpedit.msc) is one of the most useful tools for administering policy on Windows. There are several desktop, start menu, taskbar, system tweaks you can apply using the Group Policy Editor in Windows 8 | 7. To do so, type gpedit.msc in Start Search and hit Enter. This will open the Local Group Policy Editor.
In the left pane, expand User Configuration > Administrative Templates > Desktop. In the right pane, you will see a lot of settings you can modify. Most will be Not Configured. Right click on any and select Edit. From the dialog box which is presented, you can Enable the setting.
Similarly, under each category like Start Menu and Taskbar, etc, you get plenty of setting which you can tweak to your requirement in Windows 7.
Should you again wish to disable any of the tweaked setting you have to simply set it at Not Configured or Disabledagain. Visit here for a full list of available settings in Windows 7 Group Policy editor!
While Windows 7 Ultimate, Professional and Enterprise editions have gpedit.msc, Windows 7 Home Premium, Home Basic and Starter Editions do not include the Group Policy Editor. It is also available only in Windows 8 Pro, Enterprise editions and not in Home edition.
You can open Group Policy in several ways, depending on the action that you want to perform and the object to which you want to apply it. The ways in which you can open Group Policy are described here at Microsoft.
Go here to learn about Filter Options in Local Group Policy Editor in Windows.