It’s better to ask “how” and “what” questions, rather than “why” questions. “Why” questions tend to point the finger and elicit defensive answers. With “how” and “what” you’re likely to generate better understanding and explanation of the nature of the opportunity.
You might ask “how” and “what” questions such as:
How do you know this issue is a problem in your organization?
How specifically does this problem show up?
What specific proof would you be looking for to confirm that this issue was being addressed successfully?
What would let you know that your desired results were achieved?
Sales Tactics – Mastering the Art and Science of Asking Effective Questions « The Edge of the Wedge.