Windows and feet

"The doctor from the hospital came into the shop this morning with his laptop," said Keith, but now I have a problem."
"Oh?"
"The problem with his computer was that the Windows operating system needed registering, so that was all I had to do. He said he had rung Microsoft and Hewlett Packard but neither of them could help him."
"So what is the problem, then?" I asked when I had finished laughing.
"Well, can someone who is obviously so inept at the basics of using a computer be trusted with the next operation on my foot?"
"As a computer buff, he's a very good surgeon," I said hopefully.