to install .net 2003 along with it. However, the question is, for registered
files, would .net override all the file types for visual studio? In other
words, currently, if I double click, say a .cpp or .dsw file for example, it
would automatcially launch visual c++ 6.0. But then if I were to install
.net also and then double click those .cpp or .dsw, would it still open
visual c++ 6.0 or would it open visual c++ .net?

It will default to open the files with Visual Studio.NET 2003. However, you
can easily adapt to right-clicking on a given file, then selecting Visual
Studio 6, which should automatically appear as an option.