Most BIOS' also have a boot menu which allows you to choose which device to boot from; but, you're going to need a bootable device (USB DVD drive, flash drive, etc.) for it to work.
I would connect the drive to a working PC and check the contents of the \Windows\System32\Config\Regbak folder to see if there is an older set of registry files which might work. If there are, backup the existing ones in Config, copy the ones from the regbak folder, and then try booting that.
I would connect the drive to a working PC and check the contents of the \Windows\System32\Config\Regbak folder to see if there is an older set of registry files which might work. If there are, backup the existing ones in Config, copy the ones from the regbak folder, and then try booting that.