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You have already done the most important thing. There is likely to be water in the oil, and fuel lines. heavy sludge may have settled out into the bottom of the oil pan, and if an automatic transmission, into the bottom of the transmission filter.
There is also a problem that the gaskets may have all dried and lost their effectiveness especially for the head gaskets, side gaskets, and oil pan gaskets.
I like that you used fuel stabilizer, however, that might not take all the water out of the tank, especially any that might have settled in the lower portion of the gas tank, fuel lines and fuel filter.
I would like to see that you did the following:
1. You have already changed the oil and the oil filter.
2. Drain the oil again and clean out the oil pan to make sure there are no heavy metal or residue and water accumulated there, that can make their way up to the top of the engine once you start using it.
3. I would like to see you drain the fuel tank. It does not make me have a feeling of comfort that you may have a cup or more of water in the bottom of that tank.
4. I would remove and replace the fuel filter, and drain the fuel line. You have to makes sure that all the water is out.
5. Drain and flush the radiator.
6. Crank the engine without driving it and check the head and pan gaskets and make sure you still have a good seal. Look for leaks .
7. After the engine is warm (20 minutes or so), then check the power steering , break lines and brakes and master cylinder for leeks. Check the transmission fluid level. (if automatic).
8. If it is an automatic, drop the transmission fluid pan to clean it out and replace the transmission fluid.
NOTE: an interesting thing about oils and fluids, they will oxidize even when not being used, and become less useful. Their viscosity changes and can cause problems. your car was designed to handle fluids of different viscosities for oil, and transmission, brake fluid, and power steering fluids.
If you notice leaks with the gaskets, you will need to replace the gaskets with a head gasket kit. You can get a kit that includes all the gaskets: valve cover, head, side pans, etc.
When you start to drive this car again, put it on the original break in schedule that is contained in the owner's manual.