computer puzzler (with solution)

For those who think you're computer savy, here is a wierd troubleshooting scenario for you: An underutilized FreeBSD box that hasn't had significant software or hardware changes in months, on a private network. The box began to infrequently (at least at first) lock up. It would sound like it was running and if you looked at the screen it still showed the console text, but the machine would not respond to keyboard or network input. Power cycle and things would come back up fine with no logs or garbled data. The problem increased in frequency. It became apparent that a) even idle the machine would eventual fail and b) under load (heavy disk IO) the system would fail quicker.

Now stop and think about the problem and come up with your top few avenues of attack.

( The solution )