A Fast Ethernet 10100 PCI Adapter refers to a network adapter (or network interface card, NIC) that allows a computer to connect to a local area network (LAN) using Ethernet technology. The "10100" typically suggests that the adapter supports speeds of 10/100 Mbps, meaning it can operate at both 10 megabits per second and 100 megabits per second, depending on the network environment.

The Windows driver for this adapter is a piece of software that allows the operating system to communicate with the hardware (network card). Without the correct driver, the network adapter may not work properly or at all.