Hi,
It is difficult to say what is causing your problems.
I suggest you try
Recover My Files from
www.recovermyfiles.com.
Install the program on your C: drive and then run a Fast Format Recover. In the drive selection window, select and search the "physical drive" (you should be able to tell which one it is by the size). This search should take less than 30 minutes to run. Please let me know the results.