The past few days, my 3-week-old Thumby has been turning on only irregularly.  In the last day, it almost never turns on, and when it does, it sticks at the "Tinycircuits" splash screen, or gets to the start screen where it freezes up after a few down-motions of the "start" arrow.  I was able to connect it to the computer in one instance, but generally the freezing prevents it from being recognized as a USB device. When plugged in, the charging light would turn on for a second or two before switching off, now it only flashes briefly after being plugged in. When it is plugged into a computer, all that shows in the shell window is in the attached screenshot.  Tried different cables with similarly inconsistent results.
Any idea what could be going on here?