Saab
Its a SATA Raid Mirror. One of the disks had died.
So whatever took the MB out also killed a disk. The MB is dead as the PC wouldnt even boot with the raid disks disconnected.
I have switched off the RAID in BIOS and I am now running a single SATA data disk alongside the IDE system disk. Will have to save up* for a couple of replacement SATA disks and rebuild the RAID. All is well for the time being.
Thanks for your help chaps, much appreciated.
* for save up read convince Mrs Fence that it is vital that I buy them. Having recently invested in 1TB of Network storage and a new motherboard and DVD RW drive. I'll placate her with handbags and shoes