Thank you puddle glum. However, I think the problem may be a little more complex. I can get to the Clips menu using a trick to bypass the “Not enough space for music DB” message (I power on, then place the power slider to “Hold” and press the middle button of the navigation area of the Clip for a few seconds, then release the Hold to access the Settings menu. But the Sansa Clip’s own “Format” process just occupies the little device for as long as I leave it on, which has been up to an hour at a time.
When I read all the advice about reformatting the Clip as a last resort, I took “reformat” literally and reformatted the device from scratch using a disk partition and filesystem utility in Linux (I have never used Windows). As the result, I wiped the Clips flash memory clean, believing the device’s firmware would repopulate the new FAT32 filesystem with whatever directory structure and system files it needed, until I could find a way to update the firmware.
I discovered that Sansa’s “official” method to update firmware was not to offer the firmware file at all, but instead to use an application, the Sansa Updater, that is a Microsoft-Windows program only. I tried to use that program under the Windows emulator Wine in Linux, but the Sansa Updater hung at a certain point very early in the process, gave me a window but the window remained empty. I later discovered how to install firmware manually, and found the links to the firmware files themselves here in these forums and elsewhere. But by that time I had of course reformatted the Clips memory and there was no 16MB-FORMAT partition (or at least, it might be a partition–I don’t know which partitioning scheme is used in the Clips (MSDOS, with 1-4 partitions one of which is an optional “extended” partition?), how many partitions there actually are in the Clip, how large they are and exactly how they are laid out in the Clip’s flash memory, which filesystem is installed on those partitions, and what the directory structure should be and which files are mandatory.
This is the type of technical data I’m trying to find out. Easiest would be for another Linux user to make an identical image-file of his or her Sansa Clip using the program dd at a Linux terminal command line, then email that image to me or post it so that others in my position might be able to benefit from it as well. I could write the image file directly to the Clip, bit by bit, to make my Clip an exact duplicate of the good, working one. 
Steve
