Hi Linda

Click the ? button on the toolbar. It will display a ? mark at the end of
every paragraph. It could be that what you think is one table is actually
two tables, separated by an empty paragraph. If so, delete the empty
paragraph, the two tables will join up to become one table, and the heading
row will work properly.

Hope this helps.

Shauna Kelly.  Microsoft MVP.
http://www.shaunakelly.com/word