- What OS on that PC?
- What is shift-f8 assumed to do?
- A message about booting from an external drive is rather strange, assuming the hard disk works. So it's a pity you can't tell the details.
- What exactly is the "automatic startup loop"?
- What exactly are "a few of the troubleshooting fixes"? And why not *all* of the troubleshooting fixes, but just a few?
- Just a black screen means you don't even see the usual BIOS messages when it boot? Or does it mean something else?
- What exactly do you mean with "going to the BIOS and putting it in Legacy Mode" didn't work? That you couldn't enter the BIOS, that you coudn't put it in Legacy Mode while you were in the BIOS, or that it didn't solve your issue?
- Can you but from your Windows install disc or stick, the recovery drive you made or the recovery discs that came with the laptop or that you were invited to make? Or from a Linux disc or stick (free to make)?