There ARE programs that allow you to recover a partition or an entire hard-disk from the sectors that are left over. This is what the police use to see if ANY illegal files were on a computer at one time!!!!
I don't know of a software title that does this... SOOOOO do a google search on it!!!!
Also consider using programs like NORTON GHOST or ACRONIS TRUE IMAGE 8.0 to "backup" your system onto an external drive/other partition in case of you doing something like this again!!!