How do I recover my data? [duplicate]
I would suggest TestDisk which, while not having a GUI (Graphical User Interface), is free and works well.
If a GUI is important to you, consider recuva. I haven't used it, but have read favourable reviews. It also should be free.
Remember that you will need to recover files to another HDD (whether internal or external) so as not to overwrite the data you are trying to recover. You should not recover to the other partition on your harddrive which you have installed Windows on.