If your data is critical then you might want to get some software to completely erase your hard drive. There is plenty of software that will recover files from a drive that has been cleared with FDisk, reformatted and then even windows re-installed. I have used it myself on drives that have been corrupted and it recovers absolutely everything.
There is a programme here:
http://www.softpedia.com/public/cat/14/4/14-4-53.s
html
that will completely erase your data and it is free. I would strongly suggest something like this to be sure.