G5 5090, USB ports are all suddenly dead

Yesterday morning, I used my G5 5090 as I always do. I decided to shut it down because I was going to be gone for the day, possibly not need the PC until next day.

A little later I got a phone notification and wanted to check something, so I turned the system back on. Nothing connected to a USB port was recognized. Mouse, Keyboard, Webcam - nothing. I didn't have time to mess with it so I just powered it back down via the front button.

Later in the afternoon I had an hour between things to do. I did the normal check process. I unplugged the USB hub and all USB cables from the tower. Then I turned it on and started plugging the mouse and then the keyboard into each USB-A slot (front and back of machine) to see if it would get picked up. Nothing on any port. The front USB-C port isn't registering my phone or powering my watch charger when I plug those in to that port. It seems like all the USB ports just died somehow.

I have a card installed with 2 USB-C ports, which are working just fine. I connected a different hub to that & am able to keep working without the built-in ports. 

I ran a Support Assist scan & it didn't find any issues.

Any recommendations on how I can troubleshoot exactly what happened? I wouldn't be surprised if one "bank" went out, but having both back banks and the front stack of ports all go dead simultaneously just seems weird.

Thanks!