Hi I have a mid 2010 Macbook Pro running El Capitan 10.11.1. Yesterday I started it up and the computer wouldn't boot the apple logo and status bar would appear then it would shut off. I was able to but from a external hard drive and run disk utility the HD appears in disk utility but is uninitialized and the partition is gone and the drive will not mount and the options for both are unavailable in disk utility. When i attempt to erase and reformat the drive (osx extended format and GUID partition map) I get a error message of : DISK ERASE FAILED - WIPING VOLUME DATA TO PREVENT FUTURE ACCIDENTAL PROBING FAILED. I've tried the same thing after booting in recovery mode and the get the same error. Does anyone know what i can do to get the drive to mount and re partition it? Thanks.