How to prohibit installing software in XP?

Start Menu - Run - Enter “gpedit.msc”, open Group Policy, open: Computer Configuration -> Administrative Templates -> Windows Components -> windows installer -> Start “ Disable Windows Installer" and “ Forbidden user installation & rdquo;
Double-click in Windows Installer right window to disable Windows Installer check - select is enabled, click OK.
Enable in the policy: disable “ add /remove programs & rdquo;, then enable the following policy: console - user configuration - management template - system & rdquo; only run licensed Windows applications & rdquo ;, in the "Allowed Applications List", "Adding Allowed Applications and Allowing You to Run Program Limits and Limits"
You can make restrictions in Group Policy, but as long as users can enter Group Policy, Then he can still install the file, after setting the method to enter the group policy, enter the user permission settings to find the installation file item to delete all user names.