I was using my LENOVO G500 laptop, when suddenly my 2 years old kid hit the keyboard with his hand causing the laptop to freeze. when restarted I got a boot failure, and after checking in BIOS I found the HDD not detected.
I left the laptop without using it, then, after few days I turned it on and it ran normally for several days!!.
Since that, the boot failure occurs randomly (almost once a week) and always the HDD was not detected in BIOS
I removed my HDD and plugged it via a USB cable to another computer (with windows 7): it was detected and running normally!
I also ran a successful diagnostic with "Sea tools".
when putting it back in my laptop, it still not recognized in BIOS.!
Computer: LENOVO G500 Laptop
OS: Windows 8.1 64x
HDD: Seagate 500 GB