I have a 1999 Honda Accord LX V6. The Car failed the CA emissions test because the Air flow hose was cracked. I ordered an OEM air flow hose. I disconnected all the hose and the one electrical component (Mass Air Flow Sensor??) that sits on top of the throttle body. Pulled out the cracked hose and put in the new hose. Reconnected all the hoses etc. Closed the hood and tried to start the car. It hesitated then stared. I drove around the neighborhood a couple of times are parked it?
Later that evening I went to leave and the car would not start. When I turn the key there is just load clicking noises. The starter will not turn over. The battery appears to have a full charge. I did not disconnect the battery while I worked on the car.
Is the accords Anti-theft system sophisticated enough to shut down the ignition if electrical components are disconnected while the battery is connected? Or should I be looking at something else?

 

I'm guessing that the battery or the connections need attention. If you have a volt meter you can "somewhat" test the battery - 12.5v with no load, when starting it should drop a bit but not much. Clean and be sure the connections are tight.

Most all parts stores will test/charge batteries for free.