Sorry jsc, I still sit with the problem. The C drive is right up against the D drive. I have an external USB drive but Partition magic does not seem to pick it up otherwise I could transfer my D drive to the external drive whilst I sorted out my main drive.
If you have only data files, not programs on the D drive, just copy all of the contents over to the external drive, expand C:, and copy the files back to D:. You will need to make sure you don't have any linked data on D: though such as a page file or program installations and/or settings.