There are six main reasons why a system BIOS will not detect the presence of an internal hard drive. Here is a list of them. They are not in any particular order, but you can follow these steps one by one to troubleshoot this problemDrive not enabled in the BIOSSerial ATA drivers are not properly installedFaulty or unplugged data cableDrive is not spinning upIncorrect jumper settings on the driveFaulty hard driveNote Sections 3, 4,5 and 6 pertain to PC or Mac systems. Sections 1 and 2 pertain only to PC verifying that your ATA or SATA port is set to Auto-Detect or is enabled, if you find that your disk drive is not being detected auto-detected by the system BIOS, try the following steps to try and isolate/troubleshoot the problem. Drive not enabled in the BIOSMost personal computers display a brief message about entering System Setup soon after the power is turned on. System Setup is also called the "system BIOS" or sometimes the "CMOS Setup" - each is a name for the same thing. For example, on Dell systems you will see "F2=Setup" in the upper right hand corner during the computer boot-up. This means to press the F2 key to enter Setup the BIOS. Different computer manufactures have different methods to enter Setup, so please check your system documentation for your drive is not detected it may be because it is turned OFF in System Setup. Some motherboard manufactures disable unused ports in the BIOS by default. You will need to enter the BIOS setup in order to verify their current state. When you add a second drive to the system, it may be need to be enabled by turning it ON in System Setup. The Serial ATA motherboard drivers are not properly loaded. When you install older versions of Windows on a drive that will be the boot drive ie, the C drive, when it comes time to install Windows, the drive may not be detected. You might need to update the driver for your computer storage controller. Windows 2000 and XP required additional drivers to be loaded. Note These drivers do not come from Seagate; they come from the motherboard or Unplugged Data CableAlways inspect the motherboard and hard disk connections for bent or misaligned pins. Folding, crimping, pinching, or creasing data cables can cause the wires to break inside the insulation, leaving the exterior of the cable looking normal. When in doubt of data cable condition, replace SATA cables, Seagate recommends using cables shorter than inches 1 metre. For further information, please see Document ID 182453. Here are some images of Serial ATA cables. Click to expand. The BIOS will not detect a hard disk if the data cable is damaged or the connection is incorrect. Serial ATA cables, in particular, can sometimes fall out of their connection. Be sure to check your SATA cables are tightly connected to the SATA port easiest way to test a cable is to replace it with another cable. If the problem persists, then the cable was not the cause of the ATA drives, Seagate recommends using UDMA cabling with a maximum length of 18 inches. UDMA cables have colour coded connections which require proper orientation when connecting. See this image Click to expand Blue connector - always connects to the middle connector - is used for slave devices on the connector - is used for master device is not spinning up If the drive is not receiving power or receiving an incorrect level of power, it will not spin up. To check to see if this is the cause of the BIOS not detecting the hard drive, follow these stepsPower off the the computer case and remove the data cable from the hard drive. This will stop any power saving commands from being on the system. Check to see if the hard drive is spinning. If you touch the side of the drive you should feel a slight vibration. If you do not hear or feel the hard drive spinning, the drive did not start. If you cannot determine whether the drive is spinningBoot the computer and listen the computer the power cord from the computer the power cable from the hard drive in the power cord to the computer the computer up to see if the drive sound was audible before. And,Then repeat, only reconnect the hard drive and listen for it to spin power cables with a device like a CDROM or DVDROM drive, so that you are using a known-good power the power supply on your computer to determine whether it is providing sufficient electrical power to operate the drives and devices you have in your the drive is still not spinning, connect it in another computer if the drive in a SATA-USB enclosure or something similar if the drive does not spin up after all of these steps, please visit the Warranty page to begin a warranty replacement jumper settings on the driveATA It is recommended that all Seagate ATA hard disks supporting the Cable Select jumper option be configured as Cable Select. If your computer system was built prior to October 1998 and does not support UDMA 66 or greater you will be required to use the Master/Slave jumper - Click to expand Jumper settings for Seagate ATA drives- - Click to expand Jumper settings for Maxtor-brand ATA drivesWhen using Cable Select jumper settings on your ATA drive, all devices connected to the UDMA cable must also use the Cable Select setting. The cable decides master/slave device detection when the cable select jumper settings are Hard Drive