Have had this problem a few times with network cards.
1, is it the correct driver or has windows installed its own for you?
try reinstalling it!
2, go to network properties for that connection and bind the nic to the protocol
3,Go into control panel/network..
Remove TCP/IP bound to the network card ... do not click on ok
Now add TCP/IP back in...
You can now safely click ok....
You should now see the network card listed in WINIPCFG