New
#11
One thing that has not been mentioned - is the weakest link in any Ethernet installation - The cable itself!!
My first check in any install is that the cable is working - without a bespoke tester the best way to test this is by replacement, either by swapping the cable in use to a spare or by connecting another device (Laptop?), that is known to work wired for the problem PC, (if the laptop works then this also proves that the fault is with the PC)
Ethernet cables are very fragile and I've known them fail just from removing and reattaching
Maybe worth a try before reloading drivers etc :)