babygirl55 wrote:
My seagate goflex 2.5" inch 750gb drop on floor.
...
I want back my files inside ext hdd.
How to solve it??
Based on your description of the drive's behaviour, you have likely caused internal mechanical damage. Therefore IMHO you will need to use the services of a suitably experienced DR company, if you want to
try to recover the files - so you need to decide how valuable the files are to you. Being realistic, doing mechanical work on 2.5" disks is not DIY

Stop powering-on the drive - that might cause further damage, depending on what has actually happened inside the drive.