|I'm not sure about that particular model but usually there will be a panel on the bottom of the laptop you remove to expose the drive.|
My reason for mentioning disconnecting it was that if the problem was windows then maybe it was starting to boot into windows before the HP logo appeared on the screen thereby making you think the problem was elsewhere. I don't know if that's likely but it's possible.
But instead of disconnecting the drive it may be easier to slow it down by hitting the 'pause' key or the bios setup or boot order keys (if you know what they are without seeing the prompts on the screen) giving the screen a little more time to display.
Anyway, from what I can tell, windows 10 update problems are rare but sometimes happen. As I mentioned, if that's not it then some internal hardware problem is likely since you've already tried an external monitor.
Oh and yeah, it should boot from the restore disk if the DVD drive is first in the boot order and the problem isn't hardware related.
message edited by DAVEINCAPS