No concordance entries found
If you got no concordance entries, either a) there really aren't any in your text(s), b) there's a problem with the specification of what you're seeking, or c) there's a problem with the text selection. Check how you've spelt the search-word and context word. If you're using accented text, check the format of your texts. If you're using a search-word file, ensure this was prepared using a plain Windows word-processor such as Notepad.
Have you specified any wildcards (* and ?) accurately? If you are looking for a question-mark, you may have put "?" correctly but remember that question-marks usually come at the ends of words, so you will need *"?".
Bung in an asterisk or two. You're more likely to find book* than book.