NSIS (Nullsoft Scriptable Install System) is a script-driven Windows installation system with minimal overhead backed by Nullsoft, the creators of Winamp. NSIS has risen to popularity as a widely used alternative to commercial and proprietary products like InstallShield.
Being a user's first experience with your product, a stable and reliable installer is an important component of successful 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.