Thanks for the info.
savagerock wrote:forum's policy restricts linking to "warez"
I didn't realise that you meant warez in your previous comment - I guessed you meant legal utilities (but we didn't know which ones) e.g. at your workplace or similar, but with the lack of earlier details, any guess could have been correct. Now it is clear what you were hinting.
savagerock wrote:I did mention norton ghost, I've also got acronis true image.
Neither of those is sensible for this type of problem

especially now that you have given more details than before.
savagerock wrote:I ran ddrescue with -d and -f parameters and 3 retries. it read around 35 mb of the partition, then encountered an error, and then just kept on couting the "time since last successfull read". as I mentioned it's a ntfs partition, which looks perfectly normal when mounted in ubuntu, but returnes I/O errors when I try to access my data, if restarted, the disk is no longer shown in bios, but with a proper shut down it appears again.
That is vital new information. That behaviour is typical of some recent Seagate & Maxtor (STM) drives, which deliberately prevent further access until the next power-cycle, under some conditions. I have seen this many times in the past, in my (non-DR) work with Seagate drives. I'm sure the DR pros see this much more often than me.

Assuming your drive is behaving in the way that I have seen, then unfortunately that meant that as soon as the disk stopped returning data, all attempted reads of the remaining disk space (500GB-35MB) were a waste of time, and were not going to even be attempted by the drive, without intervention.

My guess is that a weak/damaged head seems likely in your case, given your description.
With previous cases on this forum of drives with this behaviour, I have not seen successful recovery using free software-only techniques. However DR companies using hardware imagers - specifically DDI - has been more successful.
If the data has minimal value to you, and is not worth the cost of using a DR company with a DDI unit (i.e. if you really want to continue taking the risks of DIY, even if that makes any subsequent recovery by a DR company more difficult / more expensive / perhaps impossible, if you change your mind later about using these services) then you could try imaging the disk in reverse (i.e. going from high LBAs towards low LBAs). This will not be successful if the drive has a weak head, for example (in this case, again errors will start quickly and then no more data will be read, just like you have seen already), but this approach may help if the problem is due to media-related issues near the low LBAs.
Other DIY approaches are possible, and some have been tried before by other people on the forum but as I said, I have not seen any that were successful, for disks with this specific behaviour. Perhaps you will be lucky and another reader has had more success than I have seen, can suggest a successful DIY approach on a drive with those symptoms.