Joke - Computer Problem

I was having trouble with my computer. So I called Harold, the computer guy, to come over. Harold clicked a couple of buttons and solved the problem. He gave me a bill for a minimum service call.

As he was walking away, I called after him, "So, what was wrong?"

He replied, "It was an 'ID ten T' error."

I didn't want to appear stupid, but I nonetheless inquired, "An ID ten T Error? What's that, in case I need to fix it again?"

Harold grinned. "Haven't you ever heard of an ID ten T error before?"

"No," I replied.

"Write it down," he said, "and I think you'll figure it out."

So I wrote it down. I D 1 0 T. I used to like Harold...