Hey guys, I bought this car a couple of weeks ago and drove it almost 30 miles. The check engine light came on and I started hearing a grinding sound from the engine. I ran the codes and it said to check the O2 sensors and the coolant temp sensor. I have replaced 2 of the 3 of these but now my car won't start. I get a rapid clicking sound when I turn the key. I have replaced the battery, the alternator and checked the voltage coming from the battery.

What should the next steps be to check? The starter?

Thanks!