That some times happens to me - and in my (computer's) case it's a bad connection between the HDD and the power supply.
please explain further, i think too that it could simply be a connection problem. what is the best way to tackle this? thank you for your responses.try the connection fix>>>>> thats a very common sata problem
there are better cables available too
the HDD does NOT show up in BIOS, I cannot select it.Hi!
Try this:
In BIOS - set the HDD as boot device #2
Check the connections once again
When you start the computer - can you feel the HDD spinning? If not - try to tighten the metal in the plug from the PSU.