Hi, as far as the grinding noise when you were driving, did you notice any change in temperature? When you tried to start it, did it sound like the grinding noise was coming from the front or back of the engine?
The good news is if it was turning, it's not frozen. The noise could be anything, water pump, alternator, idler pulley, etc. You might want to remove the drive belt and spin all of the pulleys and see if any are stuck or make a grinding noise.
If it's the alternator it will kill your battery and you won't have enough power to crank the engine.

Have you checked the actual oil level with the dip stick?
This will tell you for sure if the oil level is high, you might not have any oil, or if it's at the correct level your oil sensor might be bad. You won't be able to do this until you get the engine running again.
If it reads high you can unscrew the filter and use a vacuum pump to remove some of the oil. Start with a half quart and take another reading. Keep doing this until it hits the normal area.
The more information you can give us the better the response will be.