slowSlow, but guaranteed to work. Ask each computer if it is working. if If it says no, then it'sit is broken, if. If it says yes, then it is working. Keep this up until you find all broken computers. This works since a working computer can never say it isn't working.
Yes it's, this is not the most efficient strategy, but figured I would point out a base case that is at least guaranteed to work at least. :)