raptor_pa

If the drive is not being detected by the BIOS then there is no easy fix. First step is to ensure the drive is securely connected in the laptop. While checking that get the make and model number of the drive and post that here. If after reseating the drive, it is still not found, then try downloading the manufacturer's diagnostics from their site and see if that can find the drive. You can download a Bootable CD ISO. The next step will be to connect it to a desktop as an internal drive. If it is SATA then you can connect it directly, if it is IDE you will need a 3.5 to 2.5 inch adapter.
Post results for each step. Unfortunately tho, not detected in BIOS is usually a sign of a physical failure where the HD can't initialize( boot) correctly. The HD has it's own sort of boot sequence during the post operation.