When changing duplex to 1gbs my Ethernet dissapears.

No, It does not show any errors

but it doesn't show any error code on the screen?

Yes, I do indeed see Full duplex at 1.0Gbps as an option. And it's when I choose that it says that my Lan cable is unplugged.

In that case, the first thing we have to make sure is that our card supports the 1 Gbps connection. It is common in the most modern computers, but if our computer has become obsolete, it is most likely that we will have to replace the network card. To find out which connection our card supports, we must go to the Control Panel. In ‘Network and Shared Resources Center’ click on ‘Change adapter configuration’. With the right button on the Ethernet network adapter, click on "Properties". We are shown a window where we can see the name of our adapter and a configuration button.

Click on our Ethernet connection to access the next screen.

As we already know that we can navigate up to 1 Gbps, we are going to configure the cable correctly. In the 'Advanced' tab we select the entry 'Speed ​​and duplex of the link'. Normally the value is in "Automatic negotiation". This means that our card checks at what speed it is connected to the other end, either in the switch or in the router, and agrees with the device to transmit at the maximum that both support.

For our network, we should have the option 'Full duplex at 1.0 Gbps'. If it does not appear and we only see 100 Mbps, we will have to replace or add a new card, something very simple on a desktop computer. We can also try to update the drivers of said controller, although it does not usually improve the speed at which they can work in many cases.

I might not have been so clear, It's when I set the speed and Duplex to 1GB the ethernet disappears from my pc and it shows up as not having a Lan cable connected.