We have to get more details but if computer can’t find a drive (media) to boot up, if was working fine probably the Hard Drive is dead or Disconnected from drop, of if it never worked probably has a missing Hard Drive. Try to check in BIOS if the Hard Drive is Detected or try to run HP Hardware Diagnostics or Try to boot from a Linux Distro and see if you can see the Internal Hard Drive of get your files off.