SATA HDD NOT DETECTED IN BIOS or DISKPART, BUT SOMETIMES IT DOES. CAN'T INSTALL WINDOWS 7

.MY HDD IS NOT DETECTED in bios or diskpar sometimes it does

Hi,

Welcome to the WD Community.

Are you able to test the unit on a different computer and if possible using different cables.

To complete ERmore’s answer:

First ensure that the cable is firmly seated on both ends; on the motherboard side, there should be a slight click.

Then switch ports on the same motherboard, ensuring a firm seating.

Then switch cables and repeat the above two steps.

If you have a second computer or an external dock, try it there.