The car makes lots of juicy noises and promises, but then doesn't turn over

Hello, I have a dodge durango, 2001. My teenage driver took her out for a spin and then parked it in front of our house. It sat for two days, and when I hopped in to take the dog to the vet it would not start. It sounds like it will start, but it never turns over. There is a full gas tank, plenty of juice in the battery and I just had the oil changed a month ago. I am feeling flumuxed.

First, we need to define our terms. You stated that, “It sounds like it will start, but it never turns over”, but this is contradictory.

“Turning over” means that the starter motor is turning the engine, or you might say that the starter motor is attempting to start the engine. Is that what you mean by, “It sounds like it will start”? If so, then the engine IS turning over, even if it does not actually start and run on its own. Other than the sound of the starter motor (and perhaps the electric fuel pump), I can’t think of any other noises that the vehicle would make while you are attempting to start it.

So, before we all go down blind alleys, please clarify EXACTLY what happens when you turn the ignition key.

Anytime an engine does turn-overly things, but, doesn’t actually, you know, like start, we look for that certain spark and that fuel injected into the engine. There’s usually not a problemo with having air; so, that’s a given.
To see if it’s a fuel injecting thing, get an aerosol can of Starter Fluid (or, whichever your favorite is) and have someone to spray a shot (ok, two shots) into the big, black, plastic intake tube. Crank the engine (make it turn over). If it starts and runs a few seconds, tell your mechanic of your experience. If it doesn’t fire up, try for spark.
Get a test spark plug from an auto parts store. Have that certain someone (no, the other certain someone!) attach the test spark plug to a spark plug wire,clamp it to the engine block. Crank the engine. There should be sparks (no, not those sparks!) in the gap of the test spark plug, of one spark every 2 or 3 seconds. If there are no sparks, tell your mechanic (ok, you can tell your pal, also.).
Now, it’s in His (I mean, his) hands. If you have more Qs, we may have more As.

This (and a few other definitions) needs to be posted on a page that you have to read before posting questions on this site. So many people use the wrong terms for this, and it gets confusing.

You need spark fuel and compression.

Buy one new spark plug. Carry the plug with you and the next time it does not start, get out and pull one plug wire off (pull on the socket part not the wire) put the new plug on that wire and hold the threads of the plug tight against the engine block while you have someone try to start the car. You should see a bright blue spark, and if you are not holding the plug with an insulated tool, you will also see stars! This can rule out a spark problem.

If that looks OK then get some starting fluid from the parts store and try spraying a little in the air intake while someone is working the starter. If that sounds like it is almost running, then you likely have a fuel problem. Don’t overdo this one, read the instructions on the can.

If still no go, find a mechanic, the next steps are a little more complex.