At start up, red focus assist light stays on

At start up, red focus light turns on & stays on, LCD dispaly goes on/off & camera is ''locked up''. Only way to turn it off is remove the battereis.
If connected up an ac adapter, camera starts up fine, with indication date/time needs resetting. Once camera starts, batteries indicate full charge (non-rechargeable Lithium), but rechargeables (NiMH) show up as non-rechargeable with about half-charge (the batteries acutal approximate state of charge) . If I disconnect ac adapter with the camera on, camera will work fine (its typical picture quality). Turn off camera & it won't restart again without connecting the ac adapter.

Disconnecting the ac adapter and rmeoving batteries for more than 10 minutes to force a camera reset does not fix the problem

Camera is 6+ years old. It passes all the camera self-tests.