Pat
sounds like a battery, since it lost all SRAM data.
Yes could be auto-guider (not many people know about that one)...but best best is that is battery. Other possibilities are: Brown out detector (detecting low +5V); or the system is at the pre-set slew limit (that's why it stopped tracking).
Now since this alarm happened, not at the limit, and it stopped slewing and lost SRAM...pretty much must be a battery or loss of SRAM voltage. These batteries usually last ~ 1 year.
You can check SRAM; battery etc voltage if handy with a multimeter,
see here.