No network connections available and no network adapter in device manager (windows 7)

Hi, I'm new to this so bear with me :/

I know there are a lot of forum posts on this on this forum and many others but after 8 hours of trawling through them and getting nowhere I thought I would make a thread with my specific problem and see if anyone can help.

I got my new graphics card yesterday, and after 4 hours of trying to get that to work, it's in and working but now I have a red cross where it says my internet is connected and when I click on it it says No Connections are available. I have a wired connection, and the ethernet cable is in (there is no light on my mobo to confirm this). When I troubleshoot it says:
Windows did not detect a properly installed network adapter. If you have a network adapter you will need to reinstall the driver.

I have got my MOBO CD and attempted to do that but the gigabyte interface is completely missing and I can't find the network adapter on there. I have also tried downloading the new drivers, first on my laptop and running them on the PC but that had no success, and the second time through my Iphone personal hotspot but with the same results.

I know the ethernet cable works because I have put it in my laptop.

I have a Gigabyte H61MA-D3v Mobo
i5 2500K
8 GB Ram
GTX 770
Running Windows 7

Any help with this would be greatly appreciated because I'm close to putting my foot through my PC.

Thanks

James