The NIC is on the motherboard.  Its not repairable, the motherboard would require replacement. However, there are USB connected NIC's that you should be able to use.  Both NIC"s for wired and wireless.  This assumes nothing else was fried with the lightning hit.  Usually they do more damage than just the NIC.  
Hi! I'll start off by saying I'm not the most knowledgeable computer guy in the world. With that being said, I recently inherited an older Aurora ALX (2009) from a family member. He informed me that during a lightning storm his power had gotten knocked out. He believes this fried the NIC. I booted it up and it seems to work just fine. Of course, there is no possibility of connecting to the internet. It will attempt to identify a network, but will fail and repeatedly try identifying the network. (There is an ethernet cable connected.) I guess my questions are; How do I know for sure the NIC is fried, or if it's another issue? If it is the NIC, where exactly is it located? Once I locate it, how would I replace it, and where would I find the part? I have a manual that I downloaded from Alienware. Either I'm not reading it correctly, or it does not explain exactly where the network controller is. Thank you!
Aurora ALX 2009 fried NIC