My Saturn flooded so I replaced oil and filter, spark plugs also. Did have water in crank case but now it won't start.

SOURCE: My Saturn 1997 SL1 doen't like to start

CHECK THE COILS, WE HAD THE SAME PROBLEM SPENT MONEY ON NEW STARTER, BATT, ETC. .....GOOD LUCK

SOURCE: my car got flooded from rain water was in the engine.no start

what engine is in your car
does the engine crank?
if the engine is a 4 cylinder then it most likely has internial damage
i have done a few were its broken connecting rods

SOURCE: 2003 Saturn Ion spark plug replacement

go to autozone.com and set up a free account. You will then have access to vehicle repair guides and can get all the info and diagrams you need, plus help with troubleshooting! Hope this helps!

SOURCE: car cranks but wont start

replace your injectors. your vehicle is getting the fuel to start from the starter fluid. however the injectors arent giving it the gas that it needs to stay cranked

SOURCE: My 93 Saturn SL2 intermittent stalling issues

I would look at the egr system. First pull the valve and clean it. If you have a vacuum tester this would be a good time to test the valve itself as well. When under load you should be able to see the diaphragm engage and hold and then release as you release the vacuum. If that doesn't work check and/or replace the egr solenoid. It's located on the driver's side of the valve cover and usually runs about 60$.

Yours is a common complaint and the above is the most common remedy. Outside of that you might want to check and clean the idle air control valve and the port where it's housed. If it is extremely dirty or something managed to get stuck in there that could affect you vehicle running at idle as well.

Another thing, even though you just changed the plugs, pull one back out and look at it. If is fouled with oil you might need a new valve cover gasket which if it's leaking badly enough will impede spark.