Empty world: Molly Brown, Virus. Scholastic: London, 1994.
Starts well in a depopulated world where most of the world is sterile. Amanda is a rare 16 year old who has secured her first job as a temp at a computing firm. When she arrives she discovers that the programmers are suffering from fever and then dying. Amanda discovers that Carol, the owner of the firm, was the daughter of a women who developed organic computers (they are in all in fact her brothers and sisters). They survived a purge many years ago [when Carol had discovered they were responsible for the plague] and are out to get her.
The construction of the depopulated world is brilliant, but when Brown "reveals" that it has all been caused by computers the book flags. All of this has to be explained because its essentially an imposition on a different kind of sf novel, one which is about living in the future. The result is far too many pages of download, a segue into a rather predictable Frankenstein narrative and a rather too simplistic solution. A shame because the first half of the book is really excellent.