You blew the install somehow. Gotta set it on fire now...
Something went wrong with your install (obviously). Somehow the boot sector of your HDD is corrupted or in some other way not correct. This is easily fixed though, all you need to do is repartition the HDD and write the boot sector to the correct partition.
To do this on a non booting HDD, you'll have to boot the live USB you used for the install and mount the HDD and partition manually.
I recently did this exact thing and it still wouldn't read the boot partition, so I had to employ the /dev/zero trick to nuke the HDD so I could start over.
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