Where can I find the filter (used years ago) to filter out unwanted e-mails by subject matter?

Years ago under Options there was an option for filtering out unwanted e-mails by highlighting suspicious words.  I used this but it appears to be preventing me from receiving "changed passwords". May I had put down "Password" as a suspicious word!  In the last month the Automobile Association, Virgin and Truprint send me e-mails with a changed password seeing that I had forgotten the original Not one has turned up - too much of a coincidence!