windows 7 is old, some of the newer motherboard have new network chips that don't have a .inf file in the old windows 7 product. my new motherboard network chip was not even in the windows 8 install, I had to run them from a USB thumbdrive to get the network up.
-use another machine and download the drivers to a USB thumb drive and install them.
- install them from the CD that came with your hardware, then update them after the network starts working.
I guess you should confirm the hardware is not disabled in the BIOS, and your network cables are setup correctly