PC wont recognize HD

you might check you boot device priority in your BIOS if you haven't already. would be helpful if you listed specifics of the HDD and motherboard

On some brands of drives if the disk does not spin up in a specified amount of time then drive ready does not come true and you wont recognize the drive. Pressing the reset button if you have one will solve the problem. In other cases the system checks too fast before the drive spins up. Normally this is only a problem with aging drives. Yo can generally fix it by turning of quick bood in the cmos setup.

the priority is set to the HDD first, It might just be as azimuth stated. The computer boots up too fast where restarting fixes the problem. But I thought it might have something to do with the SATA settings in BIOS, does anyone know what AHCI Sata and Port 0-3 Sata are for? they're currently disabled.

the ahci sata option allows your sata drives to support extra features like hot plug. (shouldn't change this after windows installation) Ports 0-3 are the way your BIOS recognizes your 4 SATA drives(0, 1, 2, 3)