Don't forget that the very act of installing this software may well overwrite the files you want to retrieve! To stand any chance of recovering your files you should remove the HDD from your laptop and use the app installed on another machine to recover the data. As RMCF says, depending on how your drive was reformatted, you may never get your files back.
I always advise people to have a routine backup strategy. An external hard drive (1TB drive cost around 100 euro and are widely available) There are many apps that will image your hard drive so you never have to worry about losing your files again.
I use Acronis TrueImage, but other apps are available (Active @ disk Image) is another app I have used successfully.