If your hard drive is not recognized by BIOS there may be a connectivity problem or a hard drive issue. Were you able to use the PC with this hard drive in the past? I would start by resetting BIOS to its default settings. Go back in BIOS and check if the SATA controller is set to IDE. Check again if the hard drive is recognized. It is still missing; there may be a connectivity problem. If the laptop is under warranty, you should contact the seller.
If warranty has expired, open the laptop and make sure the hard drive is correctly placed. It may be helpful to connect the drive to a desktop PC and check if it will be recognized.