If your OS is Windows NT and you decide to install the Realtek 8139C drivers, 
    the procedures are listed as follows.


1. In the Control Panel, double-click the Network icon.If you first time to install LAN driver ,
     you should be follow the Network Setup Wizard to identify the LAN card on board , if not,
     follow the process give details about how to install the appropriate drivers.

2. Enter the Control Panel in, double-click the Network icon.

3. Click the Add button when select the Adapters tab .

4. press the ˇ§Have Diskˇ¨ icon before insert CD PRO disk into drive selected.

5. Type x:\Realtek 8139C\Winnt4 and click OK.

6. Select " RTL8139(A/B/C/8130)PCI Fast Ethernet Adapter " from the
    list of available drivers and click OK.

7. Click the OK button while the Duplex mode prompt shows.            

8. You may be prompted for network configuration information by Windows
    NT4. Seek help from your network administrator if you don't know what  to set.

9.In the Network Settings Change window, click Yes to restart your computer.