So I'm in the riddle room and I'm pretty darn sure I know the answer to the riddle (whats tall as a house round as a cup etc) . I'm going to say what my answer to the riddle is so if you havent got that far stop reading. So I cant figure out how to enter the riddles solution into the game, its has told me to enter my answer like so (Reply via 'ANSWER "answer"') but even with trying all permutations of this format i just get returned "verb not recognised". My solution to the riddle is a well but how do I now enter it into the computer for it to be recognised? It is very frustrating.

Strange, simply typing ANSWER "WELL" (with the quotation marks) worked for me. My only problem was that DOSBox had selected some foreign keyboard layout, so I couldn't figure out how to type a quotation mark. I was able to get around that by adding the line keyb sv (for Swedish keyboard layout) to dosboxZork2_single.conf, right before the _zork2.com line. See https://www.dosbox.com/wiki/KEYB for further details.

Though I rarely use DOSBox at all for running Infocom games since there are plenty of Z-Machine Interpreters out there. I don't know which is the most popular this day, but I imagine Windows Frotz - http://www.davidkinder.co.uk/frotz.html - should work fine under Windows.