Explanation :-

-> If any changes are made to the system by users,o.s,software,hardware, are all updated in the registry the changes can also be seen in the registry.

-> Using the registry only the computer starts at the time of startup windows uses the registry for the information about hardware,software,and other newly made changes.

-> Our system always maintains a backup copy of the registry with which it successfully started up last time so that it can use that information during startup failures.

-> Some of the information stored in the registry is restricted to a particular startup session.

-> Windows will make changes to the registry according to the situation and user preferences, for example when a user installs a software, windows will make the changes to registry either system-wide or user specific or in some cases both. It may also provide the user the option to choose from.

-> In some special cases registry is not available as in the case of boot process where boot.ini file is used for the process.

-> Usually the registry information is stored in c:\windows or c:\WinNT (in many files in \system 32\config folder).

-> Registry can be accessed by typing regedit.exe or regedit32.exe in run which in located at the start menu.