National Instruments interview questions

First there was a "phone screening", which was interview #1. Then they called back and invited me for a meet and greet lunch with three other associates and managers, in their company lunch room. After another week, I got called back to do a presentation (power point) about myself, and then do three interviews after that. One that was a two panel, then two three panel interviews. I didn't get called back for the second two panel interview. Questions up to that point were about the company, a little bit about the job and my experience, a lot that gauged my business knowledge, and behavioral based questions. I was under-qualified, so I had trouble answering them