How can I repair bad sectors?

Hi , I’ve got a 1T my passport USB 3 and im using it for about 2 years without any problem , but since 3 months ago I got that my hdd gets disconnected and reconnected when im coping or cutting a file from it to my PC or laptop or what ever device it is , I asked and searched a lot till I used HD Tune Pro to see if all the Health Status were OK or was there a problem with it , as it was expected I found out that so many options were either red which meant failed or yellow which meant warning , so I used Hard Disk Low Level Format Tool and format it and it took about 28 hours ( forgot to say , the transfer speed is so so so low its about 4 mb/s )

after that I checked it with HD Tune Pro again to see if the problems were solved or not , I saw that so many of them got solved and were OK except these 2 :

1.Reallocated Sector Count (Description : Number of retired sectors : 561 - Status : The drive has damaged sectors)

2.Reallocated Event Count  ( Description : Number of sector replacement operations : 58 - status : OK)

the first one  was red which as I said meant failed and second one yellow which meant warning

so I searched and searched and searched again to see how to solve bad sectors and I found that HDD Regenerator is a good thing as they said , so I got it and used it , there are there options available when you chose your drive:

1.Prescan (Show bad zones)

2.Normal Scan (with / without repair)

3.Version info 

4.Show Statistics

so I chose the first one and started scanning and after a delay my hard got automatically disconnected and after a while connected again , I continued the process and saw that after the disconnection and reconnection the program had found a bad sector , I continued some more times and saw that every time that a new bad sector is detected the hard reacts that way so I thought maybe its better to go for second option and normal scan it so I chose it and there were 3 options there :

1.scan and repair

2.scan , but do not repair ( show Bad Sectors)

3.Regenerate All Sectors in a range (even if not bad)

I gone with the first one and the same thing as prescanning happened so I thought maybe my drive gets hurt from this much connecting and disconnecting and I stopped the process , I gone with the 3rd option but it takes 350 hours ( LOL) I don’t really know what to do to repair this bad sectors 

I’d appreciate to get your help 

and something else , is this low transfer speed because of bad sectors or there is a problem with the speed of spinning ?

I used Western Digital Data Life Diagnostics and in the Quick test it fails and also it is shown fail in the smart status too before testing it , the error that appear when quick test fails is :

06-Quick Test on drive 2 did not complete! Status code = 04 (Unknown failed test element), Failure Checkpoint = 96 (Unknown Test) SMART self-test did not complete on drive 2!

Should I go any further for testing I mean , Extended test and Write Zeros?

Aryan432,

Correcting bad sectors may or may not be possible depending on the type of damage (Logical vs. physical). Logical bad sectors may be repaired by means of software, however, a deep-clean (Write zeros) may be more effective at repairing both physical and logical sectors. If a disk undergoes this process and still has bad sectors, then it would need to be replaced under warranty.

For additional information related to how to write zeros into a disk drive, please visit the following link:

http://wdc.custhelp.com/app/answers/detail/a_id/940/

i faild trying to write zeros (quick or full). Also failed the quick and extended test. 

What are my choices right now?