One solution could be to keep machine images stored, like AMIs, and use a tool like Chef or Puppet to re-deploy a known good configuration. This strategy lends itself to the case where everything is virtualized.
Of course, the source of the infection could be really nefarious. For example, imagine if someone replaced a keyboard with one that delivered a payload (trojan, keylogger, etc) when it is plugged into a computer's USB port? Then reformatting the hard drive does nothing because it will immediately infected again.
Of course, the source of the infection could be really nefarious. For example, imagine if someone replaced a keyboard with one that delivered a payload (trojan, keylogger, etc) when it is plugged into a computer's USB port? Then reformatting the hard drive does nothing because it will immediately infected again.