Nullsoft Installation System is a pretty small, efficient and very capable installation system for all Windows based systems...
Being a user's first experience with your product, a stable and reliable installer is an important component of succesful software. With NSIS you can create such installers that are capable of doing everything that is needed to setup your software.
NSIS is script-based and allows you to create the logic to handle even the most complex installation tasks. Many plug-ins and scripts are already available: you can create web installers, communicate with Windows and other software components, install or update shared components and more.
Give Portable Nullsoft Scriptable Install System a try to fully assess its capabilities!

· Generates self-contained executable installers
· Support for ZLib, BZip2 and LZMA data compression (files can be compressed individually or together)
· Uninstall support (installer can generate an uninstaller)
· Customizable user interface (dialogs, fonts, backgrounds, icons, text, checkmarks, images etc.)
· Classic and Modern wizard interface
· Fully multilingual, support for multiple languages (including RTL languages) in one installer. More than 40 translations are already available, but you can also create your own.
· Page system: You can add standard wizard pages or custom pages
· User selection of installation components, tree for component selection
· Multiple install configurations (usually Minimal, Typical, Full), and custom configuration
· Installer self-verification using a CRC32 checksum
· Small overhead over compressed data size (34 KB with default options)
· Ability to display a license agreement in text or RTF format
· Ability to detect destination directory from the registry
· Easy to use plug-in system (lots of plug-ins for creation of custom dialogs, internet connections, HTTP downloading, file patching, Win32 API calls, etc. are included)
· Installers can be as large as 2GB
· Optional silent mode for automated installations
· A preprocessor with support for defined symbols, macros, conditional compilation, standard predefines
· A lovely coding experience with elements of PHP and assembly (includes user variables, a stack, real flow control, etc.)
Installers have their own VMs that let you write code that can support:
· File extraction (with configurable overwrite parameters)
· File/directory copying, renaming, deletion, searching
· Plug-in DLL calling
· DLL/ActiveX control registration/unregistration
· Executable execution (shell execute and wait options)
· Shortcut creation
· Registry key reading/setting/enumerating/deleting
· INI file reading/writing
· Generic text file reading/writing
· Powerful string and integer manipulation
· Window finding based on class name or title
· User interface manipulation (font/text setting)
· Window message sending
· User interaction with message boxes or custom pages
· Branching, comparisons, etc.
· Error checking
· Reboot support, including delete or rename on reboot
· Installer behavior commands (such as show/hide/wait/etc.)
· User functions in script
· Callback functions for user actions

What's New in This Release:
Minor Changes:
· Fixed !searchparse (bug #2803622)
· Fixed Vista error message when canceling uninstaller (bug #2803097)
· Resolve warning for LogicLib's endless Do..Loop (bug #2849872)
· StartMenu: fixed random number prefixes when clicking on an empty spot (bug #2810188)
· Updates to NSIS.pas for plug-in development (patch #2802794)
Translations:
· PortugueseBR typo (patch #2826598)
· Removed double spaces in Italian (bug #2873598)
Build System:
· Fixed mingw builds of Math plug-in (patch #2835731)