Was this a clean install or did you reinstall macOS over top of itself? A clean install first involves erasing the drive.
The failure occurred very early in the boot process.
Try booting into Safe Mode to see if this will allow you to boot successfully.
Try booting the Apple Hardware Test (AHT) to see if any hardware issues are detected. The AHT is on the second DVD which originally shipped with the laptop from the factory. Insert the DVD while the laptop is powered on, then reboot the laptop and hold down the "C" key to boot from the DVD which should boot to the AHT.
My guess is the internal hard drive has failed, although some drive failures may not be detected by the diagnostics. I can provide instructions for creating & using a bootable Linux USB stick to check the health of the drive. Let me know if you are interested if the other suggestions don't help.