Do you think the bios has been compromised? If it is a software problem, the afflicted drive is connected to a laptop at present. I ran some anti root kit and anti virus progs on it, nothing, but an MS security scan turned up a java exploit and removed it. Copying over the disc contents I don't want to lose will finish soon and I can return the drive to my pc. First I have spare boot drive I intend to put and see if the start-up blockage is still there. I tried here in case it was a familiar problem, I think it isn't. If that is the case I should try what I can and let you know the results.
If you are suggesting using the drive to boot another pc I don't want to risk that in case it damages the bios in that one.