You can configure fault tolerance for your network connection in Windows 2000.
Simply install another network adapter and give it an IP Address on the same subnet. Configure it's Metric as a higher number than the Metric of your primary NIC. Until the primary NIC fails, it will handle all traffic, because it has a lower Metric. When the primary NIC does fail, Windows 2000 will route all traffic over your secondary NIC.
To configure the Metric:
1. Start / Settings / Network and Dial-up Connections / local area connection / Properties.
2. Press Internet Protocol (TCP/IP) and press Properties.
3. Press the Advanced button and type the Metric you want to set.
4. If you wish to set multiple Default Gateways, select the appropriate gateway and press the Edit button to set it's Metric.
5. Press OK until all dialogue boxes close.