Thanks for those links, SD - disk-wise I am kind of between the XP and the Vista scenario (I am using XP with SARTA and IDE). Disk '0' has indeed remained with the iDE. I can see that the power 'blip' may have caused Win to renumber the drives and that is fine, but I cannot understand how the drive numbering in Disk Manager is not one that will work with boot.ini - and I have to use a totally different drive number there to locate the OS drive.
It's a black art, innit?