7200, 5.01

So, wierd one here. Twice now on the same system, it stopped responding to the DM. Typical, "Check the link between DM and System" error. Usually solved with a re-boot.
Out of the blue, after a reboot, the MC flashing Red.
Took it out and checked with a reader. Blank.....
Figured, bad SD. It was pretty old.
New SD, with system files, re-booted, system DB came up. Copied to MCDB. All good.
3 Months ish later. Same DM error. Re-boot and MC light is flashing again. This time when I checked the SD card It had the DB files, but no system files at all.

Has anyone experienced something like this? Did swapping the processor fix it?

Help me hive mind, you're my only hope.

-B