Hp Pavilion p6300 series desktop will not start. After it powers on, it shows at the bottom of a black screen "Repairing disk errors, this might take a few hours to complete." So, I F9 to run tests using the Diagnostic Tool. The result Error code: A smart test failed on the drive. Error code: BIOHD-8.
The error message that you are receiving is telling you that the hard drive has failed. You will have to replace it with a drive the same size or larger than the failed drive. I hope that you have a backup of your personal data or it will be lost.