Replaced negative battery terminal with new and now no start

Hi,

I just replaced the negative battery terminal on this car and now i get in turn the key to on and everything appears normal, but when i try to turn it to start i hear a quick click and then all power is gone like the battery instantly drains or shuts off the power to the whole car. the car ran fine before i replaced the terminal. How do i fix this to make car start up? on the negative side of battery it has the normal thick wire, but then there is also a smaller wire from the terminal to what appears to be a possible body ground. Please help.