Windows 10 Desktop boot up hands at Loading Operating System

I am new to PC Help Forum. I hope I am posting in the right place for the issue I have and I can provide all the information needed for a diagnosis.

I have a number of issues with my system and will start with the first one.

When I press the start button to boot my Windows 10 64 bit, Core I5 system up, it goes through the boot up routine but hangs with the flashing message line:

Loading Operating System

because it can no longer find the boot up device, which is an SSD.

To enable me to boot up the PC, I have to press F12, this brings up a list of devices, one of which is the Boot device that I then select to enable the boot up routine to continue.

Has a registry path been corrupted? I am not sure how or why this has happened but what can I do to realign the system so that it picks up the boot device automatically again?

I will wait to hear from anyone who might have seen this problem before and can provide a solution to help me to resolve the issue.

Very Many Thanks.

Hello Folks,

I was about to try and reset the BIOS as suggested when I looked at the other two error messages I get on this PC and wondered if these error messages have anything to do with corrupting the boot up path.

When I press F12, select the boot device and boot up the PC, two messages come up, message 1 and I click the (X) to get rid of it. This is follower by message 2 and I do the same thing, exit from box:

Message 1. File Name Warning
There is a file or folder on your computer called "C:\Program ... " See attachment

Message 2. Windows cannot find 'C:\Program Files ... ' See attachment

I have attached screen prints of both error messages. Do you think this is interrupting the boot up, if so can they be fixed.

A 'C:\Program Files\WindowApps\Microsoft.YourPhone_ .....' file is likely to be a system file of sorts, how can it even be missing and Microsoft diagnostic not submit a patch to replace it. I don't remember doing anything to delete a system file.

Could be a red herring and nothing to do with the boot up, in which case I will attempt to reset the BIOS.

Nevertheless, what are these messages and where might they originate from? How can I find the cause or source of them and delete them?

The Motherboard is a Gigabyte GA-P55A-UD3.

I have decided to pay attention to these various errors and clean up my crazy PCs for once.

Thanks and I look forward to for feedback.