Network switch crashes when at least 3 computers connected

I have an auto-negotiation 10/100 Mbps switch (Addtron ADS-1008i) and four computers with 100 Mbps network cards. When I have at least three computers connected to the network, the switch eventually crashes. It usually takes between 5 minutes to a few hours. The lights on the switch showing that computers are connected turn off, and then start blinking on briefly for a while, and then they turn off entirely. The switch sometimes starts working again if I unplug some of the network cables, and it always starts working if I unplug the switch and plug it back in. It doesn't matter which three computers are connected, or whether any of them are using the network. I have no internet connection on the switch - only the four computers. All of the computers run Slackware Linux. Any ideas on how I can fix this?