My MacBook Pro Mid 2012 is shuts down while booting

Hi,

I have a MBP, mid 2012 edition with an i7 processor and 8GB RAM. I'm currently running the system on the Yosemite OS. Yesterday, I turned my the system off and this morning when I switched it on, it would shut down after the progress bar loads to around 10-15%. I've started it atleast 10 times. I've read almost every post on something related to this on the support forums and most of them recommend formatting the HDD clean and reinstalling a copy of the OS. Isn't there any other way to do this other than cleaning it?

Thanks.