PLEASE HELP ME I HAVE LG EXTEERNAL HDD HXD5 500 GB.FEW DAY ITS CANOT OPEN MY COMPUTER ITS SHOW TO MASSAGE FOR FORMATING.AFTER FORMATE ITS OK BUT I LOST EVERY IMPORTENT DATA .HOW I CAN GET MY OLD DATA

Data can get recovered either by software or by professional services. It completely depends on you what you choose...

Connect the external hard drive to your computer and run a data recovery program. Give this one a go if you're on a Mac.
Recover Digital Photo Music and Video on Mac OS

Hi
Don't use the drive at all until you are in a position to start a recovery scan.
To do this you need:
A working computer that you can attach this drive to as an extra.
Another drive (external or the boot drive) large enough to save any data
Appropriate software for the data recovery.
The software is the most difficult to specify as some are better at some recoveries than others. I have had some success with Pandora Recovery, available here:
http://www.freewarefiles.com/search.php?query=Pandora+recovery&B1.x=7&B1.y=11&boolean=exact
or PC Inspector File Recovery, available here:-
TechRadar
There are many Recovery programmes out there, you may find another you feel happier with, but both the above have worked for me.
Once you have downloaded and installed the software to your computer, read the help/instructions carefully before you start.
Basically there are three steps to recovery :
Firstly a full scan of the affected drive. Be patient this can and often does take hours, especially with larger drives.
Secondly the programme compiles a list of the files it can recover, often with an estimate of the probability of the file being intact and usable after recovery.
Thirdly identifying those files you want to recover and telling the programme where to save them once recovered - NOT the drive you are recovering from.
Hope this is helpful, if so would you please register that with Fixya
Cheers