I have both of the discs aquired by my uncle when he purchased them when they came out. Is it possible for me to use these discs with the G.o.G. version of Duke 3D? If so, how do I install it? Do I need extractors? Do I need more software? Is it possible on Windows XP? Please, if anyone has answers I'd like you to share if you don't mind. :)
GOG's version of Duke Nukem 3D is the plain DOS version running in DOSBox (though many here will recommend using the free eDuke32 Windows engine port). Anyway, if you can open up DOSBox and mount your DVD drive so that you can see your retail discs you should be able to then install them using the discs.
That said, though, I use eDuke32 and to get them working with it you will need some other utilities to extract the data files as you'll need the GRP files but two of the three expansions come with SSI files. Nuclear Winter should have the GRP readily available, but Duke it out in DC and Caribbean don't.