I cannot start up my macbook pro past the logo with the loading sign.. the bar appears at the bottom and then goes away but it just loads forever??

Turned on my macbook pro and it just didn't make that welcoming noise and the sign the apple logo came with the loading sign and that's all it does. I tried command option P and R and then the welcoming sound came but it does the same thing. I've also tried shift s and pressing reboot and return...but still no thing..helppp