I would be inclined to go to the HP site and download the network drivers for both Ethernet and also wireless network adaptors,( if you have a wireless network adapter installed) once you have safely copied these to your desktop (or somewhere where you can find them easily) check in "Device Manager" to see if there are any yellow or Red markers against your network adaptors…
Install the Ethernet driver and reboot and see if you can connect to your internet…. reboot your router at the same time…. Wait for a full 5 minutes before testing to allow everything to load after the reboots
If no joy then download and install the chipset drivers, perform the reboot on both computer and router and see if that fixes it.)
Don't forget to have your Ethernet cable securely clicked in at both ends!
So I went on over to HP website and after much milling around and not sure which of the 7 Ethernet driver i needed I saw "Chat with HP" and get this its Free
So in the end HP got my Ethernet up and running in minutes then Remote Assisted the other driver installs. Some points needed me clicking around the PC.
Knowing the id information provided in the Device Manager was the key to locating the correct Ethernet driver.