CedricThanks for the prompt reply - this is sounding less of a disaster. How would I go about reinstalling the bootloader (sorry if this is a dumb question, but I don't want to screw things up). And yes, should have been more explicit - the partitions *are* on the same box.
If you perform a google search for [reinstall grub debian] you will find easy results. (assuming you use grub as a bootloader, which is probably the case). -- Software is like sex: it is better when it is free.