I mentioned the following to my father the other day and he had no recollection:
When I was a kid, would have been early seventies I guess, I was reading a sci-fi short story about an attack on computers that brought the world to a halt. My father asked me what I was reading and I told him it was a sci-fi story about computers being used everywhere (even in homes I think) and how they were all connected and therefore vulnerable to an attack of some sort. "Why would people want computers to be connected to each other?" he scoffed.
Anyway, I was wondering if anyone knew of this story, which seems pretty prophetic now.

Could it be "Dial F for Frankenstein" by A.C. Clarke? Or the "Colossus"novels by D.F. Jones?