HDD not recognized at USB port, shows corrupted

Hi
I have taken new Portable HDD.It was working properly from last 6 months & now it is not recognized at any USB ports. I tried at various different Laptop but it is showing problam as not recoginzed this USB port & sometimes it is recognized but shows that data is corrupt & no more accessible.

Your immediate help will be graet help.

Thanks
Suvra