The code is fine, litebearer - it was the NULL value which was in one of the search fields which was causing the problem.
The table in question was originally a "flat file" - ie an html page with alphabet links to the various letters of the alphabet. Since it grew so big (298 people) and I was learning how to use php/mysql, I decided to convert over. I cleaned out all the html coding, took everything into Excel, made sure everything was in the right column, then imported into the table. During that process, I guess, mysql put NULL into any empty fields - or rather, ticked a box beside the field and that tick generated the NULL, I guess.
I've found, though, that when I use my new form to enter a record into the table, the table leaves blank fields blank - no NULL - so the searches work. Last night I sorted the table on the culprit field and manually removed the tick mark on the blank fields and now the search works just fine.
Thanks again for your initial help with the WHERE clause - it totally made the lights come on.