Camera not working with Zoom

[SPJ47]

Not sure if this is the right place to ask this - apologies if not.

I have a newish USB camera attached to my Dell PC which I have been able to use for weeks with Zoom with no problems. Suddenly today it is not working.  I can see everyone in the meeting they cannot see me. I am just a black square.

Yes I have clicked on the small video symbol so the red line is not there. My camera responds to Zoom when I do this as the blue light on the camera comes on.

I have checked that the camera works via the app in windows 10 - it does.
I have turned off my PC and rebooted/ changed USB port - no improvement
I have uninstalled and reinstalled Zoom - no joy.
I have checked my PC privacy settings and yes, Zoom is shown as one of the apps that can access my camera.
I have checked my settings and I only have one camera - “USB camera” and that is shown as the one Zoom is finding.
I have checked for updated drivers and windows tells me my driver is fine.
I have tried with my OH’s camera and that’s not working either, even though it has its red light on.

I have now run out of ideas. It is frustrating that the camera  been working fine for weeks and now suddenly it’s not.

I'd be grateful for any help/suggestions. Thanks