@cpernu
This is a desktop, right -- so open the case and confirm that the 2TB SATA drive that came with this PC is still there. And while you're at it, confirm that both the data cable and power cable are connected to the drive.
If all of that is OK, then reboot your PC, pressing the ESC key repeatedly, and when the HP Startup Menu appears, select the option to run diagnostics (usually F2).
If there are no Diagnostics available, then the previous owner likely trashed the BIOS and you bought a dead PC.
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