The "Genius Bar" guys at the Apple Store checked error logs in the machine and found what appeared to be problems in the RAM memory. But when they attempted to run a RAM diagnostic sequence, the machine locked up on them. Their final evaluation was that it may be a main processor problem.
The Apple Store is shipping my Powerbook off to California for repairs, which are covered by the Apple Care agreement. They said the usual turn-around time is seven to ten days.
In the meantime... desktop PC. Meh.
In other non-news... I attempted to run for the first time since I fell ill. I only made it a mile. The one mile took 8:44. I was reading an article in Outside Magazine about running last night which suggested that a "slow jog" or "resting pace" should be... about a minute faster per mile than I can achieve by pushing it! Thus, I'm feeling pathetic well beyond my usual level of pathetitude.