Please clarify or post an image of what you are seeing (or perhaps not seeing).
Is it missing from device manager?
Do you have any problem devices in device manager.
Can you share some information regarding your system.
Manufactuer Name, Model Name, Model Number, what ethernet card you have installed???
IF you right click the Start Button and choose Run and in the Run dialog box you type
ncpa.cpl
and hit enter or click OK.....
What do you see.