Hard drive data recovery? Rush

A little piece of age, there are important information.All of a sudden can not find the boot hard drive, how could not find, machine-for-ah, what a friend does not have
understand how hard it can be, or to find Inside information, thank you,

simplest and most effective way:this removed the hard disk, to install in another computer , So this machine has two hard disk, you can see if you can see the original hard disk information? If not, it is estimated that there are hard issues, may have to take a professional to help the store.