any tool you use, be sure to stop using that hard disk, the less you use it, the more likely you will recover files from it
as mentioned, there is many tools to recover
there is tools like trinity rescue and other linux boot cds and usbs that will offer multiple tools as other tools with a windo style boot menu, whatever you ecover, be sure to put it on another hard disk
my prefered tool to recover files form situations like this is photorec
http://www.cgsecurity.org/wiki/PhotoRec_ES
the problem it has is that it recovers everything, and usually doesn't recover names, it puts a generic name
another option is recuva
the easiest way to do the process is connect this hard disk to another pc and on that pc try one of those tools, recuva or photorec
both are free
the task can take many hours
this process recovers the files, it will not repair the partition so it will boot again, only recover files, all files, so be patient, this includes temp folders, windows folders, all folders on hard disk
there could be a tool to repair or unformat the partition, but i never use those since is more common to have a damaged hard disk and save files with photorec than a accidentally formated unit so i never attempt to recover partition