In that case you should not test the drive before you recover your data. This is because if the drive has physical damage, it might get even worse with a full scan.
For data recovery you could try to access the HDD via Ubuntu Live USB/DVD (this is basically a bootable, freeware, portable version of Linux), to see if the drive is properly recognized and if you can get to your files. Another option would be to try out different data recovery software options like the ones suggested in those links:
http://www.tomshardware.co.uk/forum/id-1644496/lost-data-recovery.html & http://pcsupport.about.com/od/filerecovery/tp/free-file-recovery-programs.htm. And last, but not least, if your data is really valuable, perhaps you should consider the most reliable option of all - a professional solution, such as a data recovery company.
I really hope you're able to get your files back. Please keep me updated.