Q: Macbook pro freezes on startup

I just bought myself a new Macbook pro. And I have a problem.

I changed the permissions off the Machintosh HD disk to read and write. When I tried to start up it firstly gave me a black screen after logging in. Then when rebooting it freezes on starup screen halfway

I also tried to boot it safe mode, but when starting up I can't hear the startup sound, and when hold shift while starting up gives me no result.

I hope somebody can help me solve this