Multiple problems after updates

I run a dual boot Win 8.1 and Win 10, with the latter just for gaming which I haven't had much time for recently, so I haven't booted into it that often. So when I did a month or two ago there were a bunch of updates.

I'm not exactly what updates there were but I think it included 1803. Either way, loads of things went wrong after that. For example it was taking ages to login to Windows, I think it just showed a blank screen for all that time. I did a scan and repair which fixed that problem but I still have others including:

Right-clicking on taskbar icons doesn't work. I have to hold shift+rightclick to bring up the menu.

Clicking on the systray "Actions needed" icon briefly opens the Windows Defender Security Centre window (all blue) before it closes itself.

Under Settings - Accounts - Family & other people, clicking on "Add a family member" or "Add someone else to this PC" briefly opens a grey window titled "Microsoft account" which then closes itself. I note that under "Your family" it says "We can't connect to Microsoft family at the moment" but that might just be because I'm not logged in using an Outlook address.

I guess I may have to just do a fresh install but before I resort to that I thought I'd ask if anyone has any ideas how to fix it, not least because knowing what went wrong might help me avoid it happening again in future.

Thanks but the slow boot problem was fixed by a scan/repair.

I just ran InSpectre and it shows Yes, Yes, Yes, Good (not sure how my system is protected as I haven't updated the BIOS recently. There's a beta BIOS update for my Asus Z97-A dated 26 April 2018 but I haven't installed that yet and the previous one is 18 November 2015.

With the taskbar icons it's the right-click jump list that doesn't work at all, nothing happens, only if I shift+right click then I get the context menu.

So yeah, it seems pretty messed up. I probably did make an image a while ago but it's probably quicker to do a fresh install from the latest ISO rather than restore my image and go through the process of letting it update, reboot, repeat, to get all the updates installed.

I will change the update settings to give me more control in future though and then I can ensure I make an image before allowing it to update.

Thanks but that didn't help. Literally nothing happens still when I right-click on tasbar icons.

I see a lot of errors in Event Viewer for the Windows logs - Applications relating to various applications that all reference guard64.dll, which is part of Comodo Firewall, so I'll uninstall that and see if it helps.

Yep, that seems to have done the trick. Now right-clicking on the taskbar icons works, as does clicking on the search bar, the Windows Defender Security Centre window opens now, as does the Add new user window when I select "Add someone else to this PC".

Need to find a new firewall now, I wasn't that keen on Comodo anyway. I might try Tinywall although I found it a bit buggy on another PC when trying to use the global hotkey to add a window. I think I'd prefer something with popups personally as I know what to allow and what not to.