Hi,
It may be already a case of a bad HDD but do try these troubleshooting steps that may help.
- Do a hard reset first, remove the battery and AC adapter then press and hold the power button for 20 seconds then try the Recovery process again.
- Next is to reset BIOS to default then try running the Recovery.
- If it would get stuck again, I would run a Recovery again but this time using a System Recovery disc that you can get from Samsung themselves.