Because Adama refused to network his ship's computers, the Galactica remains the only capital ship unaffected by the Cylon virus.
Number Six , a Cylon in human form, reveals herself to Gaius Baltar , a brilliant scientist whose unwitting cooperation allowed the Cylon virus to bypass colonial firewalls. The Gathering: A New President and an Old Ship Battlestar Galactica - T1 miniserie.zip
Battlestar Galactica Miniseries Part 1 - sciphilconf.berkeley.edu Because Adama refused to network his ship's computers,
With the central government destroyed, , the Secretary of Education (and 43rd in the line of succession), is sworn in as the President of the Twelve Colonies aboard a civilian transport. a Cylon in human form
The planetary centers are decimated, and the human race is pushed to the brink of extinction.