offers two probably relevant programs for data recovery and partition recovery (not free).
2. Data recovery
Even if you can't recover the partition structure, there's a chance you may recover some files using a program that scans your disk. How successful that may be and whether you retain the filenames depends on what corruption has occurred.
For data recovery, Diskdigger, Recuva are popular
PC Inspector File Recovery
Pandora File Recovery
(free) offer scans for files.
(You need more than jsut recover deleted files).