IN which Programming language Windows Server 2000 is written?

Windows is not written in a specific programming language. The entire operating system itself is based on a kernel, which is written in Assembler, C, C++, and a few other high-level programming languages. If the Operating system were just a compiled program, people would be able to decompile it, which Microsoft does not want to happen. So, a variety of languages are used, compiled, and those are compiled together to make it. Sometimes, a programmer must use some binary for it to complete a function, and then they run it so it can be decompiled again, hence being closed-source. Linux is an open-source operating system that you can edit to your will. They give out the source code, and the kernel, so you can make your own operating system.