MSSQLSERVER service does *not* start, port 1433 in use
Find out what process is already using TCP 1433.  You can do this through the use of TCPView.  That utility is a sysinternals tool that gives you the information you need.  Just start it, pause the data view, and look at which process is using the local port of 1433 with the TCP protocol.

Note: You'll probably want to uncheck "Resolve Addresses" in the Options menu item so that you will be able to see the default instance port number.

Then once you know the process that is already using that port, you can take the appropriate action or reach out to the appropriate personnel that may know more about the process, why it's there, etc.

Or you could always change the port in which your SQL Server instance is listening on, but I'd personally be extremely curious as to which process is already using that port.