You need to write that hdimg file as a disk image to the USB stick, not just copy it there like a file. Win32 Disk Imager can do that for you from your PC. Then boot from it on X5000 and repair whatever SFS filesystem is damaged. Or just format and reinstall MorphOS.

I'm afraid that there's only a limit to how much people can help. If you're not able to do basic tasks on a computer or follow basic instructions then you need to ask someone around you for help. Maybe a carer?