140 Floppy Solution -- While you're peering around for your PowerBook 140's serial number to see if it's hot, check to see if your machine has the shield that solves the intermittent disk recognition problems that have plagued 140 owners. PowerBook 140s with a serial number of F2149 or later (PowerBooks made after Christmas, 1991) had the shield installed in the factory and will not experience this problem.
As we reported a few weeks ago, the immediate solution is to turn off the backlighting on the screen, and the long-term solution is to call Apple at 800/SOS-APPL and make arrangements to send it in to be fixed, a free repair I believe. Do note that this repair deal only applies to the 140, and not to the 170 or the 100.
Mark H. Anbinder -- email@example.com