The Microsoft .NET Framework page contains:
"The .NET Framework is the programming model of the .NET environment for building, deploying, and running Web-based applications, smart client applications, and XML Web services. It manages much of the plumbing, enabling developers to focus on writing the business logic code for their applications. The .NET Framework includes the common language runtime and class libraries."
You can install the .NET framework on Windows 2000 and Windows XP.
If you are NOT a developer, like me, installing the .NET framework will allow you to take advantage of freeware tools and enhancements that Microsoft will release from time to time.
NOTE: I installed the .NET Framework on a Windows 2000 domain controller, Windows 2000 Professional, and Windows XP. I was NOT required to restart these computers.
NOTE: For Windows 2000, Microsoft recommends that at least Service Pack 2 be installed. It installed fine on Service Pack 3.
See the Code Prompt Explorer Bar freeware.