Cranks will not start

Has plenty gas and brand new battery. Was leaking water from somewhere. Coolant light kept coming on and had to put in water about two times a day. Did not run it hot! Make a strange sound when cranking it. Actually after crank, like you were hold the key a little too long even though you did not. Water leak stopped. Coolant light stopped coming on only had to put in water once every two days. I have no idea why it changed. Starter got stuck on twice just for a few seconds in the previous week. Then while driving went shut off will not start. Will crank but not start. Makes noise like it is going to start but never does. Starter stuck on while continually trying to get it to start. Only had three weeks. Please help.