I CANNOT ACCESS ANY SETTINGS

Hi,
I was reading Brink's post on changing account pictures in Win 10 as I cannot change my account picture on my Dell Optiplex. Noticed: C:\Users\Public\Public Account Pictures\S-1-5-21.......(GUID for user account).

I have read Brink's: How to Fix Manage "File does not have a program associated with it" Error post
but my problem is almost the same but with Win 10 SETTINGS...

Dell OptiPlex 745 Desktop with Win 10 Pro 64 bit.
Just done a driver update and my dual screen setup works exactly as it did before the Win 10 upgrade with no tweaking. I USED THE SAME Radeon DRIVER for the X1300 display as I used for an X1400 laptop and wonder if this has caused an issue......(although I think the same driver is available for both displays and there is even a ATI_multi-device_A04_R160911 driver.)

I CANNOT ACCESS ANY SETTINGS - HELP!
I have a: This file does not have the program associated with it for performing this action.... message
which appears if I right click on the desktop and select personalise or screen resolution or try to access any setting. This error first occurred when I tried to change the account picture from the start button and right clicking on the nasty grey icon. In all three situations the screen briefly flashes white. I have no way of knowing whether this was the case before I updated the driver. I did roll it back and got the same problem although, then only one of my two screens had a display whereas immediately after the Win 10 upgrade both were on and mirrored each other.

I have been Googling this issue but so far solutions proposed are for rather different symptoms such as not being able to access folders or the message popping up when right clicking on "Computer" to manage it in Win 7.

Would really appreciate some pointers on this on please folks.

Thanks,

Mike.