Employee Names includes the company name?

This is quite an annoying problem that I'm not able to fix, nor is our NS consultant that sold us this product who provides support for us as well.

When we first started using NS, I had setup all of our then current employees into the system, but something happened around April 2006 that changed the way names are displayed in the employee section. For example, prior to April, all employee names added to NS show as XYZ Corp : Doe, John, but then after April the new employee names are just listed as Doe, John.  This causes a problem because this splits the company employees with half that have the company name in the front and remaining half doesn't have it, so when we're entering support cases and trying to search for the employee using the drop down box, we have to search both by alphabetical order AND remember to search for those listed with the XYZ Corp in front of it.  I've already tried all the routes to attempt to fix it, however it appears this is some underlying code problem that won't allow me to disassociate the employees with the company name.