Hi there and welcome
Can you please remove the power cable from the Asus then hold the power button down for 60 seconds then release.
Then connect the power cable, power it on and tell me how it now starts please.
how long have you left it complete when it first happened? As it can take an hour or more to complete
ok, power it off.
Then power it on and keep tapping F9 until you get to a recovery manager
Can you get to this?
ok, choose troubleshoot, then system restore.
choose the last restore point then tell me if it then starts please.
ok, then you need to choose the option to reset your PC but keep your data
Programs you will need to install again but you cannot avoid this.
Let me know how you go please.
How did you go?