I have 10 older computer I have used over the years for LAN gaming. Average age 7 years. They all have sat in storage for the last 3 years. Took them out of storage this week to set them up and only half will turn on. The power supplies work, I have a tester. The light is on on the mother board. I even changed the battery on the mother boards. They still will not turn on. Thanks for any help.