on another PC, Download the Intel Rapid Storage Technology (RST) Driver or the Storage Controller Driver. Ensure you download the F6/Extractable/ZIP version meant for installation during Windows setup, not an .exe installer
extract the files to a folder named DRIVERS and copy the folder to the USB drive
plug the USB back into your broken PC and boot to the Command Prompt again
Find your USB drive letter again
Navigate to your drivers folder by typing: cd Drivers (or whatever you named the folder).
type dir to find the driver file ending in .inf (usually named something like iaStorVD.inf or iaStorAC.inf).
type: drvload filename.inf (replace filename.inf with the actual file name) and press Enter.
once it says the driver successfully loaded, type diskpart and then list disk. Your internal hard drive should now magically appear.