Another silly question. Does it appear in Admin tools/computer management/storage/disk management?
Yep it does... that's why it was so perplexing.
Well in case any of you are interested we solved the problem quite simply in the end.
turned out to be a dodgy EIDE ribbon cable.... changed it for another and it is now working fine in XP. It was very odd as the drive was working with the old cable when booting direct from the CD and also with the Windows 7 test partition we installed on it. but discarded as it ran too slowly.
The other odd thing was that the USB dvd drive did the same thing
I have been working It since the mid 80s and computers never cease to amaze me with their little issues
Well the kids are happy and so am I as it was really stating to bug me