Ghost in the Machine (1993) on Netflix

Karl Hochman, a technician in a computer shop, is also "The Address-Book Killer", who obtains the names of his victims from stolen address-books. Terry Munroe and her son Josh come into the store to price software, and a salesman uses Terry's address-book to demonstrate a hand-held scanner. Karl obtains the file, and while driving to Terry's house that night in a heavy electrical storm, his car runs off the road and lands upside down in a cemetery. While Karl is undergoing a CAT scan at the hospital, a surge of lightning courses through the building, and Karl's mind is transformed into electrical energy. Karl uses the electrical grid and computer networks to continue his killing-spree.