What I mean by "partition editing" is that I used a partition manager to transfer free space from the D Drive to the C Drive. However, the power went off, during the process.
Sorry for not being clear.
Therein lies the problem. Of course your D drive would be inaccessible! Your computer doesn't know where the heck the D drive starts anymore!
Like Patio said, make an image of your C drive (or the entire hard drive if possible) and start over. You may have to wipe the entire hard drive and repartition it, so if you can image the entire drive, by all means do it.