My desktop computer is connected directly by ethernet to the router.  I also have a tp-link Nano USB adapter (TL-WN725N).  I was able to use my PC as a mobile hotspot, but now, although I can connect other devices (like my phone, laptop) to my mobile hotspot, I get a message showing 'Connected (no internet access)'.  I previously had this issue and with some messing about between the router settings and my PC settings, I managed to get it to work, but I have no idea what I did (I'm not very computer savvy).  Any suggestions? Preferably explained in simple terms.

Just to confirm, if I use my laptop, connected via wi-fi, it works perfectly as a mobile hotspot.  However, if I connect my laptop to the ethernet cable, I get the same problem.  I suspect there's a setting on the router?