Hi attid
Since you can boot from the integrated disk, let's try booting with just what's needed to get a display.
Add the boot code nousb and unplug all USB devices for good measure. In the BIOS, disable any
integrated devices not required for booting (network, sound, etc.). The intent is to try to get the system
to boot at a normal speed. If we achieve that, then we can start adding devices back in to try to identify
the source of the problem.