Do this next:
In the Device Manager, select the Unknown device with the yellow question mark (the one you mantioned before), Select Update Driver\ select Not at this moment, click Next, try first; “Install software automatically (recommended)” and click Next,… If the driver doesn’t install, it may be that the previous driver was somehow deleted, so you need to find it in the Internet.. So to know the correct driver you need to find, download the application Speccy, install it.. and run it… in Network, on the right pane the first line should describe the Network Adapter… if it doesn’t have a description, go to the line “Motherboard”, the second line on the right pane should describe the motherboard model.. with the mouse, select the motherboard model, select copy to clipboard, and paste the copied text to a web browser search page… from list of results, click on the link that names the motherboard website and look for a description or downloads tab or link, and look for a Network Adapter driver. Download the driver and execute it as I instructed before to start the installation and follow the installer instructions. When the installation has finished you should have internet access and if it doesn’t, restart the computer and try a web browser.. if you still don’t have Internet access, go to the Device Manager repeat my instructions at the beginning of this message…
Post back any results.
If you prefer, use Speccy to get the motherboard make and model and post it here so I can search for the Network Adapter driver… and if possible, include the Network Adapter make and model.