This occurred sometime over the holidays while we were away visiting. Daughter's computer can no longer connect to the koala network via wifi; every attempt results in a "Can't connect to this network" error. Tried forgetting the network, restarting the computer and the router, flushing the DNS cache from the command prompt.
Son's computer (wired directly to the koala router) works fine. Daughter's computer works fine on other wireless networks. Any ideas for the next step to take?