Was the "no luck" for screwing the rod back on or valve would not open after successfully screwing the rod back on?
Can you see the rod that goes into the actual valve move? Not the one with the handle you pull.
You say absolutely NOTHING flows when the valve is opened? Not even a trickle? 100% dry?
If that valve rod DOES move you have obviously got a MAJOR blockage. The snake idea MIGHT work. But you will likely damage the valve seat. But, at this point you may have no choice. When it unblocks - LOOK OUT! It's gonna be messy BIG TIME. Unless you can do this at a dump station.
If you do damage the seat it's not a big job nor expensive to replace the valve. Much easier to do with the tank empty. (As if I needed to say that:hihi