Q: why wont my car start? on 1997 BMW 528i

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when i bought it the seller said it needed a new water pump because it would over heat. i replaced water pump and thermostat.i test drove it and water was coming out of the cap so i shut the car off. the car did not start again until the next day. i replaced the cap,the car started and when i shut it off it did not want to start again.we replaced the radiator and i do have the master key but the car still wont start.the key turns over and all dash lights and radio comes on but the car doesnt start or make any noise...we flushed the lines so there is no air...whats the problem???
(1) Answer
See if engine turns over by hand (or with a socket on end of crank) If not pull plugs and check for liquid (most likely anti-freeze) in cylinder(s). If you find liquid in cylinder(s) then you've got I think, 3 possibilities; 1) simple blown head gasket ,2) blown headgasket and crack in cyl. head or 3) trashed block. Almost sounds like they knew why they were selling it, sorry . I HOPE I"M WRONG!............brief explanation- liquid in cylinder will cause 'hydro-lock' , liquid can't be compressed so piston will not move , hence no crank from starter.