Then either the HDD died or the Windows install is damaged and needs a reinstall.
I would use a Live Linux stick to look at the drive, which you can make using one USB stick and
Unetbootin on a different computer to create the Live Linux (that runs the OS from the USB stick, something that Windows consumer versions cannot do).
Your other choice is to boot from a Windows installer CD and use the command prompt to look at the drive in diskpart. The problem is most Windows users don't have an installer disk.