best internal usb?

Solution
Since the front ones work, the motherboard usb adapter should still be ok and the drivers should be ok.

Yes, a pci/pcie adapter card will do the job.
You have an opportunity to get more functionality also.
If you do not now have the faster usb3.1 you can get that, as well as type c output.
I bought one of these for my son's pc.
We needed the internal adapter for front panel usb3.1, but that would not be needed for you.
There are others, but this particular card worked well out of the box:
https://www.amazon.com/Mailiya-Express-Connector-Controller-Internal/dp/B01MQ5R7I1/ref=lp_229185_1_17?s=pc&ie=UTF8&qid=1519916105&sr=1-17
What usb ports are you talking about?
Is this a new build, or were they ever working?
Those on the rear of the motherboard, those in the front of the case, or what?

If all of them are not working check in device manager for bad or missing usb drivers.
You might see a yellow exclamation mark for a usb adapter.
 
Since the front ones work, the motherboard usb adapter should still be ok and the drivers should be ok.

Yes, a pci/pcie adapter card will do the job.
You have an opportunity to get more functionality also.
If you do not now have the faster usb3.1 you can get that, as well as type c output.
I bought one of these for my son's pc.
We needed the internal adapter for front panel usb3.1, but that would not be needed for you.
There are others, but this particular card worked well out of the box:
https://www.amazon.com/Mailiya-Express-Connector-Controller-Internal/dp/B01MQ5R7I1/ref=lp_229185_1_17?s=pc&ie=UTF8&qid=1519916105&sr=1-17
 
Solution