If you think your computer's hard disk has been damaged or if you have mistakenly deleted important data the only way to preserve it and then later retrieve the data is to clone it by yourself or go to a specialized center where it will occupy for you to do this.
If you plan to clone the disk by yourself you need another harddrive to copy the data from the damaged one; you will proceed trying to recover data not from the damaged harddrive but from the one on which we made the copy to preserve the original as it would be hazardous to work on the same risking to lose permanently the files that we are trying to recover..
. you can clone your hard drive with the software HDD Raw Copy Tool (you will find the download link on bottom of the page that will open).
To extract the files from your copy, we need Photorec thanks to which we will transfer all the files that will be able to recover on our computer and then save the ones we wwant to restore and discarding others.
It is very important, however, that if during the HardDrive Recovery it emits strange sounds or freezes you interrupt the operation immediately and turn it off. Before you start it is also important to check the status of the hard disk via CrystalDiskInfo that shows us the "State Disk", by reading the SMART data, and that with a blue icon, yellow or worse, red, tells us if the disc is dying rapidly and in such case it is better to turn off immediately to avoid losing definitively the content.
If you can not recover the data you need to contact a specialized center findable with a simple search on the Internet; prices of recoveries ranging from hundreds to thousands of dollars depending on the status of your hard drives, the type of file to recover and depending on who will perform the recovery - it may be cheaper than buying a second hard drive to clone the damaged and run the self-recovery.
Once contacted the center Hard Drive recovery must send your disk and they will clonate and recovery data in a manner similar to that described above. Only in very rare cases and very unfortunate (hard disk or computer fell on) they will need to open the hard drive in clean room and in this case the cost will go up easily over a thousand euro and the chances of recovery will be almost null (2%).
However, a personal recommendation is, to rely only on specialized centers with headquarters and laboratories in your country because scams are not rare and cases where, once the damaged hard disk delivered to the mysterious collection company, you can not regain possession unless you accept the proposed budget and pay the amount requested. Just make a Google search to find many examples of complaint.
When using a laptop or an external hard drive is good to be careful not to move it and do not drop it even from a few inches in height, especially if it is turned on. It can still happen always a failure or a data erasure random independent of our poor care.
In both cases, it is good to evaluate whether it is worth to attempt data recovery in terms of time, stress and in economic terms. My personal thought is that often data such as photographs are considered fundamental but they are not, maybe that bind us to past memories but often is good the loss of such data and allows us to start from scratch and to focus on present and future. Unless we are speaking for example about photos of relatives who have left us, and in this case myself I'd do anything to restore those photos.
Finally, it is always advisable to save important data on different disks and sometimes cloud services avoiding files that we would never want to go in the hands of strangers.