VS.Net will run on NT only if you have the latest service packs installed, same with Win2k. You will have to install the IIS server component and you can do that in the control panel, under add/remove software. You need your CD. You also have to install some Data Object component from the MS website. I forget the exact name. VS.Net is better than VC++6. The huge problem with VC++6 is that it does not meet the C++ Standard. The C++ STL is not supported. In VC++7, which is different than VC++.net, because the latter targets the .net framework, you can write Standard C++ applications using the C++ STL.
The best tool for learning C++ is still the Linux OS using g++. I've recently used KDevelop and it is very nice. It's similar to VC++6, except it allows you to use C++ STL. Instead of Win32 you can use QT which is a GUI emulator and actually runs on Linux/Unix, Windows, Mac, and Solaris, however you have to install the library on the target machines, it might be possible to deploy it within your application, I'm not sure. At any rate, these are the very best tools, and for reasons that you will not be aware of for several years, however in many cases the Linux OS is simply too much for any beginner to deal with.
VS.Net would be good, however it is expensive. Win32 is okay, however it is limited in the sense that the programmer is volnerable and at the mercy of the implimentors of the API (Microsoft). At an advanced level it also does not support research, learning, understanding, or new ideas. I would say to learn the API, however be very tentative, and try to get away from it if you can. Once you learn C++ than you can learn OOP design. I would say that only about 4% of the members on this board are cognizant of OOD.