Need help with Ethernet controller after yosemite upgrade (Macbook pro 7.1, 2.66Ghz)

[japmeet]

Hi, a few months back I upgraded my macook pro 7.1, 2.66ghz, to yosemite via the app store update thing installation (I made a bootable USB and formatted the hard drive and installed yosemite fresh)
Ever since then my ethernet has stopped working. Network panel under settings doesn't show ethernet (I've tried the + sign, different locations, assist me has ethernet greyed out)
Under system report, osx tells me that I don't have an ethernet card installed. However, when I connect a LAN wire from the macbook to the router, the router's port lights up.
I've run AHT as well and I get the "no trouble found" message.
I've tried installing a bunch of kexts I found online, messing around with the IONetworkingFamily kext to no avail. I've searched the forum and looked all around but I can't seem to find the solution.
I would really appreciate if someone could help me figure out what's wrong as my current situation dictates that I have a working ethernet port (lab work at the university).
Thanks!

 

[P1LGRIM]

Hi, a few months back I upgraded my macook pro 7.1, 2.66ghz, to yosemite via the app store update thing installation (I made a bootable USB and formatted the hard drive and installed yosemite fresh)
Ever since then my ethernet has stopped working. Network panel under settings doesn't show ethernet (I've tried the + sign, different locations, assist me has ethernet greyed out)
Under system report, osx tells me that I don't have an ethernet card installed. However, when I connect a LAN wire from the macbook to the router, the router's port lights up.
I've run AHT as well and I get the "no trouble found" message.
I've tried installing a bunch of kexts I found online, messing around with the IONetworkingFamily kext to no avail. I've searched the forum and looked all around but I can't seem to find the solution.
I would really appreciate if someone could help me figure out what's wrong as my current situation dictates that I have a working ethernet port (lab work at the university).
Thanks!

This question is more suited to the Apple support forums, but I would suggest reinstalling the operating system over the top of your existing setup.

https://support.apple.com/en-us/HT201372

 

[japmeet]

This question is more suited to the Apple support forums, but I would suggest reinstalling the operating system over the top of your existing setup.

https://support.apple.com/en-us/HT201372

I'm most probably gonna get the following answers there:

• Take your original installation dics and reinstall OSX : The laptop is from 2010, I don't have the installation discs.
• If you don't have the original discs, buy new discs and reinstall OSX : Superdrive is busted and does not work
• Take it in to apple care : No more warranty and they'll charge me ~ $600 or something to replace the logic board (I read in the engineers' manual that when they get an ethernet not working case, they replace the logic board)
• Buy a new macbook : I'm a student and don't have that kind of money. If however I were to buy a new laptop I'd go for a Dell XPS or something so that's out of the question.

The reason why I posted here was I was wondering if anyone here had the same laptop model as I do and could tell me which kext plugin I need to install in order to get the ethernet working again (as I mentioned earlier, LAN light on the router lights up when I connect the ethernet cable and AHT says there are no errors)
I've looked everywhere but I can't figure out whether its an intel nic or an apple bmc nic.
Basically the make of the nic