Hi, Michelle. The problem can be that the stlye attached to what you're searching for has an attribute that makes Word overlook it. This can be frustrating, however, as you have found. Start by checking the Language settings of the relevant paragraph style to make sure that detecting spelling errors is on. I think this is Tools/Language in 2003; I haven't used it in a long time; it might be under Edit.

Best,
Ulodesk