The registry can be edited manually in Microsoft Windows by running regedit.exe or regedt32.exe in the Windows directory. However, careless registry editing can cause irreversible damage. Thus, performing back-up for registry is needed. Many optimization and "hacking" tools are available to modify this portion of the Windows operating system. It is preferable to use one of the many registry tools available, unless you have a knowledge of registry workings or wish to learn more about the registry, in which case it is recommended that you back up your hard drive before changing the registry.