This is most likley the third Ethernet wired network that your desktop has connected to. Each time you plug the Ethernet cable into a different device it will identify it as another network.
To view all networks that your PC has connected to (including the current one)...
- Right click the network icon in the bottom right of your screen (the one that looks like a screen with a trident to the left of it), then click Open Network and Sharing Center
- There you will see Network 3, click the icon for Network 3, then in the resultant window click Merge or delete network locations
You can manage your network connections from there.
This does not slow down your PC, it is purely a name for the network that you are currently connected to.
It is not a 'step', it is a description of your current network setup. Disable the network and you will most likely disable internet access.
Tricky