Vista - problems with acronis secure zone and windows vista

Hi. I wonder whether anyone can help. I recently istalled a trial version of
acronis tru image and created a 40 Go partition as a "secure zone" on my C:
hard drive. The program did not seem to work as it should and I tried to undo
the partition but unfortunately it was no longer accessible and could not be
reformatted
using acronis. Acronis support could not help and in any case it was a trial
version I used, accessible for 2 weeks only . I lost 40 Go of HD space but
the worst is that the windows restore facility does not work anymore since it
does not recognize the reshaped C: drive. With the disk manager I can see the
40 Go partition which appears as unallocated space but when I try to reformat
it I get an error message saying available space is insufficient. Is there a
way out? Thanks in advance