Why does my laptop boot slower and get stuck in startup

Gmann

I've had the Acer predator triton 500 with i7 9750h and rtx2060 for about 2 months now and it has been working excellently for the first month and a half. Recently I connected it to an external monitor through mini display port for multitasking. The monitor is a dell s2417dg. For a while  it worked great but then as I was shutting it down one day the fanned continued to spin even after I shut it down. I wasnt sure what it was doing so I just forced shutdown by holding the power button. When I tried to turn it back on it booted up and said no bootable device found. I unplugged my mini display port cable, force shutdown and booted it up again. It booted up, although a little slower,  perfectly fine. After a while I didnt really have a problem with that anymore. However the other day i was shutting it down and the same thing happened, fanned still spun for a while so I forced shutdown. Then I unplugged my mini display port cable and tried to boot it up. It went to a blue error screen and then went to the predator loading screen and said preparing automatic repairs. I've since then just left it alone. Is there any reason why this Is happening,  or is there any way to prevent it? Please and thank you.