10.6 crashes average of every 12 hours A couple of days ago, my Snow Leopard Mac Mini started to crash an average of once every 12 or so hours. Symptoms include the display being frozen (no changes in response to any keyboard or mouse input), and being completely unresponsive to network connections (ssh etc.; I've turned off the firewall on a NATted network).

What are the logs/diagnostics I should be looking at to figure out why it's crashing?
You should go to Console.app to see the logs (before and after the crash) and try to find a repeating pattern.