Thanks for the tips. This is a laptop that I am using since some time. I cannot change the hardware in it. All I can do is to replace the HDD, but it is working fine for now.
Did you suggest not to use the same partition because of bad sectors ? I think that is a good argument. But if I can somehow manage to bypass the bad sectors in that 100 GB partition, I could actually use Windows 10.
It is not that I do not understand your solution. This is the hardware I got and I have to use it until it fails ( because it does everything fine now ). If there is a workaround which allows me to use Windows 10 as well, it would be great.