How can recover data from free agent desktop hdd

OK! Don't panic! Nowadays, the formatting process will not actually erase the contained data on a memory card or hard drive. The data is still there and only becomes invisible. That's why one always has chances to get back their lost data back from a formatted hard drive as long as it is not overwritten by anything new.
So, I hope you've not saved anything new on your hard drive.
Download a formatted drive data recovery freeware that can easily restore your wanted data back from this formatted drive for free:
http://www.4cardrecovery.com/
In fact, I find it as my camera memory card is also accidentally formatted. It eventually restores all my needed photos, videos and files back successfully. So, it can be a good chance for you.
Just read more detailed information of this freeware here:
http://sd-card-format-recovery.blogspot.com/2013/11/recover-sd-card-after-formatting.html
PS: Do not forget to back up everything important well in the future.

OK! The bad sector is always the terrible killer of memory card/hard drive data. Therefore, if you are sure there are some bad sectors, part or even all of your original data may be gone already. That often depends on how badly your drive is damaged.
But, that's not to say, you have no any hope to get back your back. In fact, as long as they are not completely killed, you do have possibilities to restore them back.
Simply go try a formatted hard drive data recovery freeware that always can help easily restore all inaccessible data back completely from a formatted drive:
http://www.formatrecovery.blogspot.com/2013/02/recover-data-after-formatting.html

It has offered a special "Format Recovery" mode for you to process your formatted drive data recovery problem.
Note: Next time, you'd better never format your drive or memory card without any data backup.

Well you should have gone in and marked the sectors that you think are bad, by formatting it odds are you wiped the data off it, you can try a low level recover but I dont think your going to find much. Sorry format means format.