When I ping 127.0.0.1 (localhost) what exactly does this tell me if I get replies. If I get replies does this mean that my nic card is good.

PING is a command that is used on networks to verify connections to other computers. It is an acronym for the words: 'Packet INternet Groper'. A computer on the network is identified by what is known as an IP address, which consists of four numbers separated by dots, such as 127.0.0.1. However, there is one address that cannot be used by any computer in the world, and that address is 127.0.0.1. The reason is that this address has been reserved as what is known as the loop-back address. A loopback address is an address that tells the computer not to test its connections to another computer, but to test its own basic network setup. Source/check it out: Here

127.0.0.1 is a address for yourself. If it replies successfully you nic is good and so are the drivers if not check the drivers and sometimes a cable needs to be in and active.