COM port assignment used to work, but no longer

My MKR WiFi 1010 worked fine for quite a while, then recently it's failing to initialize a COM port on my Win 11 machine.

The board is powered with 3 leds showing there is power. The ON led is steady, the CHRG led is flashing at about a 5-10 Hz range and the third led, over near the 5V header location is constantly on. I believe the third led should be pulsing at about a 1 Hz rate.

I've also tried a power only cable to see if the last program would start. Same result.

The board did display some inconsistency where it would work sometimes, then not other times. A few days ago it was working fine. Then after being powered down overnight the next day I got the condition I outlined above.

I've tried this on 2 different computers, one Win 11, and the other Linux Ubuntu 24.04. It used to work on both, now neither.

The reset button does nothing at all. Double clicking also does nothing.
Grounding the reset pin next to the dio14 pin also does nothing. The schematic shows the reset button and the dio14 pin are in parallel.

Originally I prototyped my circuit on a plug board, then once I had it all correct, I soldered everything together intending to put it in a project box. The circuit has an AD9850 DDS signal generator, an encoder to set the freq, and an ST7789 display. That's 14 soldered connections that I really don't want to remove unless I'm completely replacing this arduino.

Any idea how I can proceed? Note that the pads on the underside that could be used to connect a debugger are not accessible.

Welcome!

That could be a lot of things but without knowing exactly what you have we probably cannot be much help. Post an annotated schematic showing exactly how you have wired this. Be sure to show all hardware items including resistors etc. Show how you have powered it and what the sources are/were. Post links to post links to technical information on the hardware items.