The Paris Option by Robert Ludlum

An explosion shatters a laboratory in Paris. Among the dead is the creator of a molecular-or DNA-computer. Suddenly, US fighter jets disappear from radar screens, all telecommunications abruptly stop, and the entire US begins to shut down, with devastating consequences. Only the power and speed of a DNA computer could cause such havoc. Following a trail across two continents, Covert-One-agent Jon Smith uncovers a web of deception that threatens to reshape the world....