It was an english drama shown on ITV or Ch4 around the mid to late 90's. It was about a guy who received a CD/Game through the post. He became immersed in it and strange occurances started happening. When he killed someone in the game a similar murder took place in his neighbourhood. When he stopped playing someone threatened to kill him. It may have the name cyber or net in the title. I've tried google but no joy. Any ideas?
