Sometimes windows won’t boot unless I switch off and on again

In last few months (maybe only since fall creators installed but that may just be co incidence) I have had issues when switching my desktop on. It’s happened about 3 or 4 times where it goes past post and then nothing happens. I’m still stuck staring at the ASUS logo on the loading screen but there isn’t no attempt to load windows. The spinning dots don’t show at bottom of the screen. When this happens there is no keyboard illumination or anything. The desktop is all on as I hear the fans spinning and all the lights are on. But the only thing I can do is tap the power button on the desktop which switches the machine right off. I then turn it on again and everything loads up fine. It’s an SSD so after POST it’s just a few seconds. This is pretty rare as it’s only happened I reckon 3 or 4 times since September-ish but it’s just slightly worrying. I wonder if it’s a windows issue or maybe a power issue. I made sure the power supply was firmly in but it happened again since. The pc is connected to a UPS but I doubt the UPS is at fault because it also powers the monitor and an imac and they never have this issue. I thought maybe the BIOS could be to blame so I updated that as I was very out of date but it’s happened since that was updated. I even checked reliability monitor to endure the shutdowns were clean and there are no complaints in here. It can’t be heat either because the times it has happened can be shortly after it had already been on or after a whole day or so of being off. I know it’s clutching at straws a bit but has anyone experienced similar maybe since fall creators ?

I have repaired many computers with your problem it is always caused by failing HDD/SSD drive but your case is strange if the storage drive failing i'm not sure how powering your computer off and on will boot the computer.

Disconnect all externally attached devices to see if computer boot issue will resolve.

CrystalDiskInfo (free) is an easy-to-use, open-source program that can shows the S.M.A.R.T. health status reported by your hard drives.

thanks, i think the drives are ok but i will run that tool. I wonder if the internal card reader is causing issues. There are no devices with exclamation marks in device manager but basically that thing doesn't work on the machine. there is nothing in it but a few months ago it decided to stop reading anything in one of the multitude of slots that it has. Trouble is it is internal and so it's not like I can just remove it.

See if you can disable card reader from BIOS if not disable it from Device Manager.

Time will tell, as these issues can be pretty much anything, software and/or hardware related. You could also try a different PSU, if you have a spare one.