The customers were initially disappointed but I could totally understand why - I would have been if I had been in their shoes. They thanked me for letting them know and were pleased that things had been carried out as expected. The computers came back online approximately 50 minutes later and shortly afterwards m manager returned. I explained exactly what had happened, what measures I'd put in place and what else needed to be carried out. I also made some recommendations in case this happened again. As a result we have a revised dedicated procedure in place for dealing with system down time during core customer opening times. I also received a nomination from my colleagues for employee of the month for the way I managed the customers and supported my colleagues.