I want to know if I delete my HDD data permanently then does it goes out fully or keep on somewhere in the drive. I want to put up for sale my hard drive . I had formatted every partition of it, but is it possible to recover data out of it? Any help regarding this topic is appreciated. Thank you.
Yeah it is very imp to delete all the sensitive data b4 u get rid of ur old system.The simplest way to do this is to format all the drives,but that too may not delete all the data and there are always chances to recover them.I can suggest you 1 tool that will remove all ur data permanently forever and no other tool can also be able to recover it.“Advanced System Optimizer”,
has a tool named Secure Delete that does the permanent deletion of the data,but be cautious once the data removed can not be recovered anyhow.
U can download its free version from cnet
Well whoever wrote that magazine should be told off then for providing factually inaccurate data in this instance.
It’s been proven by digital forensic science that formats do not remove data effectively (which is why no security expert in their sane mind would rely on it). 
Maybe. Or maybe my interpretation is not perfect or there’s more info that I’m not writing here… or maybe, he was not an expert and you know better 
I may be wrong. I’m not a hardware expert but this is something I’ve read in a magazine specialised in computer security. I would assume that they check what they write. I’m sure that this option is not the best though. Just one low level format takes hours.
Sorry but you’re wrong Nuria, you can format a disk as often as you like, however formatting simply marks the clusters of the HDD as empty and ready to write over… even on a deep slow format it won’t erase the data. The ONLY way to ensure that data cannot be recovered is to overwrite every sector of the disk and the MBA using a tool like Eraser (which bundles junk data into those sectors, scrambling what existed previously).
I use a linux live CD and a linux program named shred which writes multiple passes of different bit patterns on all data areas of all sectors. Formatting usually doesn’t rewrite the data portion of a sector, and there are programs that can scan for and recover information from freshly formatted drives.
You need to at least format your HDD seven times (the slow, slow format, you can’t use the fast format). This will ensure that data can’t be recovered.
Also, as Scallio has suggested, you also use a specialized software
Yup, if you just format the drive the data can be recovered. It’s not trivial to do this but not very hard either.
There is specialized software that let’s you wipe the data of your hard disk in a safe way. Basically what it does is write the whole disk with random 0s and 1s several times.
An example of this software is KillDisk, but there are many more software packages available to achieve this.
What you think about here is the 7-pass erase.
For many years some security experts had the opinion that you had to overwrite the disk with random patterns of one and zeros - i think i heard about this for the first time for some 12-14 years ago.
However, there is still a debate going on here, as some security experts claims one time is enough, while others claim it must be done at least 3 times, but 7 times to be secure - then you have Gutmann and the 35-pass overwrite 
You also have disk degaussing, which wipes it all, but makes the disk unusabel - some claims the disk can be usable again by returning it to the manufaturer for service - the data will still be lost after doing so…
I think that was it, yes
It takes a fair bit of expertise and expense to pull data off a formatted drive, nevermind something that’s been through a 7 pass erase. If someone wanted your data that bad, they probably aren’t going to wait for you to ebay your hard drive . . .
When my laptop refused to work one morning, I try to format HDD 4 times .It was working again.
After one day , I remembered that it had some data that was important . So how do i recover data?
I took it to IT repair people who recommended Rapid. After they performed the diagnostic they estimated a 40% recovery. They said if I tried Fields they would be able to give a better recovery because they have better tools for invasive recoveries. I was very happy with their services.
I forget who said it, but I heard a great quote about hard drive erasure one time:
“The only way to really erase the data on a hard drive is to remove it from the computer, hit it multiple times with a hammer, and burn it.”
Formatting will not do much. Most data recovery tools can recover a lot of data after 1 or more formats. Something like killdisk overwrites the individual sectors with other data. I know of no commercial software that can recover after a DoD wipe.
If you are really interested in how low level data recovery is performed and how to protect against it, read this article:
http://www.cs.auckland.ac.nz/~pgut001/pubs/secure_del.html
And here is software that implements it:
http://eraser.heidi.ie/
You can also make bootable disk using this utility (similar to abovementioned killdisk).
I was trying to delete my data permanently and the thing work for me was 7 pass erase.