internal hardrive not recognised el capitan

computer crashed after el capitan install, wont boot in safe mode wont go to cmd r for recovery after 5 seconds screen fills with Panic CP2 caller ox

Process exec of sbin launched failed erno 2'@ source cache etc etc

internal hardrive not recognised by macbook pro , now screen doesnt work, using external monitor and usb backup drive with time machine to get on here , but macbook only picking up old backup of time machine ie from 6 months back with older osx not the yosomite backup i know must be there somewhere , how could i access yosomite backup and get going again with internal hardive help

many thanks