whoever was the person that gave or sold you that used PC you need to ask him to either give you the PC Driver disc or have him burn you a disk with all the drivers needed for your motherboard like the CHIPSET Driver, Ethernet Driver, SATA Driver, etc.
Or you can find someone with a computer with internet and download all the drivers you need from the motherboard's Support site on to a USB Flash drive.
If you don't know the Make & Model of your Motherboard then get a copy of SPECCY from someone else on a USB Flash drive and install it. It will give you all the information on your computer including Make & Models.
Or you can go to Windows Device Manager and under "Network Adapter" try to manually install Windows native ethernet driver or hit "Driver Update" and see if it installs the ethernet driver automatically. But you need to know the Make & Model of the ethernet chip your motherboard is using.
My motherboard uses Realtek ethernet driver as an example.
