I had Mikrotik Router OS on x86 PC. My hard disk and PC is very old and I want to move the RouterOS to new PC and hard disk. I have Router OS's license key and software ID for the old hard disk.

Is it possible to move this license to the new hard disk and how to that?

RouterOS licenses are bounded to the HDD.

You can move the HDD from the old PC to the new, but you cant move the license from one HDD to another.