Mac won't detect start up disk
I have a macbook pro 15" Retina display late 2013. When I start my MacBook it will show a question mark in a folder. I tried to select the hard drive but nothing is there. sometimes it will let me log in. ill use it and then it will freeze. ill turn it off and restart and it will be the same problem with the question mark folder. Not sure what to do.. I have looked all over the internet trying to figure it out. Please help.
Is this a good question?