I've already checked this, but I'll try again after the machine finishes a 24-hour memory check. What log files should I look at then? The machine is old and may have intractable hardware problems, but I can use it a little longer if I can get Knoppix running with persistence. It boots reliably only from the DVD drive. (The external USB drive is the only other functioning drive on the machine, and it comes up as sda.)