Missing drive

We have a Windows 2000 pro computer, with 2 physical drives.
After a reboot, Drive D, a dynamic disk, dissappeared completely from Disk Manager. Event viewer reorts a bad block on the disk. The physical drive is picked up by the BIOS, and can be seen from a Windows 98 boot disk (FDISK). My gut feeling is that I have had a catastrophic failure, but, as it is not seen at all in disk manager I thought there may be an underlying Windows problem (especially as the OS must be able to see the disk to report the ‘bad block’.

Any ideas please?