windows 10 freezes after startup

Windows 10 Pro running on Dell 5810 desktop, as upgrade from windows 7 64B. Win vers.1909, build 18363.778
The problem:
At startup, after regular boot and UAC completion I get a regular window with Fences correctly run and several start apps regularly run. But missing Outlook 2016 run and I suspect that this is the reason for the problem.
What I get is a mouse pointer that becomes a circling ring when I point to the lower bar.
To unlock I have to click on windows key or force any of the icon in the lower bar. The screen becomes black for 2 seconds and then the system becomes unlocked.
At this point I must manually run Outlook 2016, despite it is included in the start apps.
I did hundreds of attempts to solve the failure and googled for hours. Windows automatic repairs, reinstallations of Outlook, editing of Start Apps, editing of registry "run" . I have not reinstalled windows 10 as I would like to avoid apps reinstallation. Pls give some hint. Thanks

Since a faulty driver may freeze the system, I would first update all the drivers. I would also check all startup applications and disable those that I don't need when Windows start. Right-click on the taskbar, select Task Manager and see the Startup tab. Also malwares/spywares consume too many resources and freeze the system. Download a tool like Superantispyware and do a full system scan. Remove anything found and restart. I would then use CCleaner to fix any Registry issues. Run it 2-3 times until no more errors found.

Finally to check for errors in system files and correct them, open a Command Prompt as Administrator and run the following command:

sfc /scannow

first let me thank you for your attention to my problem.
I am sorry (for myself ) as I have already done any of your suggestions but the driver check and I will do it also.
For what malwarebytes is concerned I have uninstalled and check if that could solve, but no change. BTW I agree that MB take a lot of resources, but I proved in many years that it's a very good tool to protect and I am under russian and german frequent hacker attack to my Synology cloud.
Thanks again, in case I will get some result from driver check I will report. My personal opinion is that could be some installation problem due mainly to Office /Outlook 2016 but I am very near to give up.

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To solve I made as usual the long and tedious job of disableing all the apps listed on startup and one by one uninstalled and reinstalled. So doing the system was unlocked probably due to some app interfering among others.
This solved the spinning circle but not the automatic installation of Outlook. So I deleted one of two profiles listed, leaving the correct one and removed all the addons. So the startup also worked. Now I hope it will last for sometime.
Pls let me thank all of you for the attention to my problem.
Ciao
Manlio