As for the random terminal sleep issues, some machines can be pretty bad, particularly if they use the magnetic sleep switches.

For the Wallstreet, if some hard drives are installed, the computer will go into terminal sleep because the armature magnets in the drive interfere with the reed switch (which is mounted directly above the hard drive bay), causing the machine to sleep as soon as the desktop loads. The only real fix is to get a different hard drive. Fujitsu is always a safe bet for those 'Books.

All modern 'Books use magnetic reed switch sleep, and sometimes the switch goes bad or, in iceBooks, the little magnet next to the optical drive is knocked loose during a disassembly session.

For older, mechanically-engaged sleep mechanisms on pre-Wallstreet models, the switches can get stuck or go bad, especially if the machine is open and closed very frequently.

So, if your PowerBook has a terminal sleep (or refusal to sleep) issue incurable through other methods, check the sleep switches.