If it's a hardware failure, it was completely without any physical shock to the camera--and only a little over a year after its purchase. I don't think the battery failure /necessarily/ caused the problem, the two things juts coincided. Given the symptoms, I feel a software glitch is more likely (speaking from my non-camera IT experience) than anything else and I'd like to rule it out before I go any further. I know that CHDK is not a firmware replacement, it's only a firmware 'extension', but I figure, in order to write a tool that works with the existing camera software the way CHDK does, someone has to have access to compilable code for the original Canon firmware. That's what I'm looking for.