if your customer had a falling out with the integrator and they had access to the pc, I hate to say it, but they may have gotten into the pc and erased the critical programs and files needed to obtain the information you need. I would look at the deleted filed. Warning, be careful of what you find. they may have changed the files before deleting them, if that is what they did.
I have known of this happening, not saying they did.
james