The .NET Framework 1.1 is a component of the Microsoft Windows® operating system used to build and run Windows-based applications. For developers, the .NET Framework makes it easy to rapidly create powerful software that maximizes performance, scalability, opportunities for integration, reliability, security, and the end-user experience, while minimizing the costs of deployment and management. For more information, visit the .NET Development section of the MSDN® Library.

Applications built for the .NET Framework require that the .NET Framework be installed prior to running. The .NET Framework Redistributable will install the .NET Framework onto your machine.

Generally speaking, your application vendor will alert you if you need to install the .NET Framework to run a particular application or will install it for you as part of the application.

With the number of .NET Framework-applications on the market growing rapidly, we encourage you to install the latest version of the .NET Framework, if you haven't already.

You can check to see if you already have the .NET Framework installed by clicking Start on your Windows desktop, selecting Control Panel, and then double-clicking the Add or Remove Programs icon. When that window appears, scroll through the list of applications. If you see Microsoft .NET Framework 1.1 listed, the latest version is already installed and you do not need to install it again.

If you are using Windows Server 2003 the .NET Framework 1.1 is installed by default.

You will need version 1.1 to run applications built using the .NET Framework 1.1. Applications built using version 1.0 will run just fine on version 1.1 of the .NET Framework Redistributable. The application vendor should inform you whether or not you need a particular version of the Redistributable to run the application.

For more technical information, see Versioning, Compatibility, and Side-by-Side Execution in the .NET Framework.