Hoping you can help me.

MY computer currently has two SATA drives installed, one on RAID0 with the OS installed, the other is newer, on RAID1.

The second of these drives does not get detected by the computer's BIOS, and therefore is not detected by the OS either.

The second drive is a 1TB Hitachi.

Since acquiring the new drive, and finding that BIOS did not auto-discover it straight away, I have swapped the power and SATA cables over between the new and old drives.

The old drive continues to work whilst the new drive continues to not be detected, therefore this is not an issue with the cables.

Fortunately, I have a third SATA drive in a portable case, so I have opened the case and swapped the portable drive with the new drive.

The new drive works fine in the portable drive case (detected via USB), but the portable drive itself (now in the computer) is now not detected.

The issues appeared to me to be something with the BIOS, so I downloaded the appropriate Gigabyte BIOS utility and updated the BIOS. Updating the BIOS had no effect except that once the OS (Win 7) was booted, it thought it had discovered a floppy drive (I rebooted and edited the BIOS, it seems flashing the bios caused it to change the "FLOPPY DRIVE A" value to "enabled" whereas before I had it disabled).

The motherboard is a Gigabyte K8VT890-9

Does anybody have any suggestions as to what the cause of this issue may be, and how to get around it?

drive with OS installed is on SATA0 and new drive on SATA1. Any suggestions, anyone?!?!