Sorry, DELL-Chris M. No such luck.
I tried what you suggested
After that failed, I let Dell's "Detect Drivers" app tell me what drivers were missing & tried to install them. Some (that were already installed) were successful but several failed, saying "Not correct for this laptop". Then, I downloaded ALL of the drivers for the Inspiron 5748 laptop & tried to install them, one by one. Again, those that were for hardware installed in my laptop were successful & the rest were not.
Through all of this, I still have the same three "Unknown" devices.
Any other ideas?