Will not start?

I was given the car listed above because the previous owner was having trouble. It appeared to have been a rundown battery, so they put in a heavy duty one, but the car seems to have a phantom drain. I charged the battery, and it seems to hold a charge. They had lost the key, so today I got it back from the locksmith and tried to start it. Nothing. Turning the key to the start position does not get it to crank. Lights and nothing seem to work. I am at a loss as to where to begin.

Crank sensor?
battery ground cable?
stater solenoid?
electrical problem?
a sensor somewhere?