Yo all, just a quick heads up of your still having issues, this post led me to the solution to my problem so thanks to both for a start.
I have an Sony Nec ad-7630a drive, I got this as a replacement drive for my Toshiba A120 Sat Pro. BIOS and Windows would not see it, I downloaded the file Optiarc_7630_ATAChange_Tool.zip from http://liggydee.cdfreaks.com/page/en/Optiarc-AD-7630A/ .
I had to get the drive attached to a PC to use the conversion tool, I sued this http://www.maplin.co.uk/Module.aspx?ModuleNo=36947&doy=30m11&C=SO&U=strat15 .
I changed the ATA setup on the drive to â€œReverse ATAâ€. This works a treat.
I'm posting this in detail as Toshiba were no help what so ever and google only gave me half the answer, so for others trying... there you go.