For a very simple minded count on a single word, you can use your doc program (Word, etc) to replace the word with the same word. Most programs tell you how many replacements were made.
Just be sure to set "match case" in both the find and replace boxes, or you'll change them all to whatever is in the replace box.
If you really want to go "whole hog," save a doc under a new name - to work with. Replace each space with a paragraph break (^p in the search/replace box in Word), then select all (Ctl-A)and "Table - Sort - by paragraphs," which will put all the words in alphabetical order. (Note - if you're short on RAM, sorting very large selections can take quite a while, and it may look like you've locked up. With 128MB and a clean machine, you should be able to sort a couple hundred pages of "one-word" paragraphs.)
Look for the words that repeat most frequently, and highlight the list of one of them, - use Tools - Word Count to get how many times that word occurs (using the "paragraphs" count for the selection).
It's a little more work than a real "analysis" program, but you should be able to get what you're looking for.