If anyone I know gets a virus on their computer and wants me to fix it, I don’t bother with anything past antivirus protection. If that doesn't remove the virus, I reformat and reinstall the OS. The US military doesn't always have that option when it comes to drone flights. The Predator and Reaper drone sin the US military arsenal are used for missions ranging from attack to covert surveillance.
About two week ago, the Airforce discovered that the computers at Nevada Creech Air force Base where the pilots of drone missions control their craft from were infected. The military claims that no classified information has been leaked outside the network; however, the virus had survived more than one attempt to remove it.
One source claims that each time the virus is wiped, it comes back. The virus is believed to have infected the classified and non-classified machines at Creech. The full scope of the infection is unknown. The virus is suspected to have been introduced to the network by flash drives used to move data about missions between computers.