Sounds to me it's your clutch or tranny thats done. How, I can't tell you, but it sounds like that you've got no clutch system left or that your tranny is NFG, or even both. There are many issues possible. Either way, your tranny has to come out. I doubt it is the master cylinder because then you would be able to move the vehicle because the clutch would always be engaged. Look for issues once the trans is out. Even if you can diagnose the issue without taking the tranny out, its got to come out anyway so may as well start there.
Once you've got it out, I would start with a visual. If everything looks O.K with the clutch and tranny, I would test the slave. Simply connect it to the hydraulic line and pump the clutch, see if it moves in and out. If it does, I would then test the tranny. Try to turn the input shaft when it's in first, second, reverse, whatever, and see if the output spins. If it spins, it may be O.K. If not, there's your problem. I say "may" because it still could have issues which impede it's function.
Needless to say, in summary, this is probably not going to be a cheap repair. I can't say what the issue is, only guess, and my guess is that you'll find the problem upon removal of the tranny.
Hopefully I gave you an idea. This is what I would do, but others may have a better idea. Good luck.