Mac only sometimes boots, screen goes black randomly, delayed reboot

My laptop screen has started to go back at random times. Sometimes it will flip back on after a minute or so and sometimes I have to hard restart it.

The same problem has recently come up when I reboot it. The apple and the spinning wheel will show and then the screen goes back to black. I don't know if it's the screen only b/c I do not have an external monitor to hook it up to.

When I *just* tried to restart my machine it would not restart, until I walked away from it. 2 minutes after trying to reboot it it finally decided to reboot.

My fan has been very noisy lately as well. What should I do (I'm pretty sure I should replace the fan)